Regarding eccentric best friend characters

[Agentt]

These characters refer to the weirdly cheerful and idiotic best friends that MC has in order to force him to activate or break a flag. Some famous lines include,

"Let's peek at the women's bath."


....
I actually can't remember any, but none the less, that one line should be enough to tell you who I am talking about. These ultra shounen characters who do embarrassing stuff in public to act as a foil for the mc.
They sometimes also help MC by telling him the chest sizes of all the girls, along with their hobbies and likes-dislikes.

These are also the characters who would score low in exams, and then force MC along with all love interests to attend a group study.

The problem with these is, I am not quite used to their cheerful language. Or rather, their toddler minds are quite out of grasp for me.

So, how would you write one?

 

[Biggest-Kusa-Out-There]

basically this:

all of those little things they do come across as distractions from their own issues. If you've watched Nisekoi, Shuu Maiko is this type of character. Silly when in school with out of pocket behavior/commentary that, when put under the magnifier, show a not-so-happy origin or daily life outside of these particular moments.
Usually they are extroverts who are opposite of the straight-man protagonist that is usually an introvert so the reader can relate.
Their actions are usually to the service of either the plot as you mentioned, or to service other characters in the form of providing information that the invtrovert mc would otherwise never know of.
It has to be pointed out, too, that mc's are usually also socially inept otherwise you have a seamless plot progression and character interation that the majority of readers simply cannot relate to. These clown characters serve this purpose of being socially adequate and 'in the know' of matters surrounding the social circle the mc is a part of. They are crucial to oil the social cogs by bringing in information as I mentioned above, and usually kickstarts certain plot points that mc's would not think about due to their limited social capabilities and/or the energy they have to perform these activities.

Or, you can write them stupid and a plot device.

 

[Cipiteca396]

Watch some Old Disney TV shows. Or maybe some new ones, I don't know, I don't watch TV now that I have internet.

I guess you could try some school anime, but the tropes are different because of the culture clash. The peeking is one of the biggest ones. I've seen some horrible things happen to people just because they got caught in the general area. Actually doing it would probably be fatal...

Maybe watch some Fails videos, Bronze league gameplay, or TikToks and try to understand what the people were thinking.

For general advice, you've already got the important bit. If the character is meant to be the MC's foil, then just think, "What would be the LAST thing the MC considered doing here?"

Usually I don't go for this sort of thing though. Instead of aiming for 'weird best friend', I just give them a few normal traits and see how that stacks up.

I spent so long looking through TVTropes for a reference that you could use, but there's so many tropes, I...

Spoiler

Zany Scheme - TV Tropes

A Sitcom plot where one or more characters tries to achieve some end — usually extricating themselves from trouble — by some kind of elaborate, unlikely plan, something like "You distract them by faking a heart attack while I sneak …

tvtropes.org

Hormone-Addled Teenager - TV Tropes

In fiction, teens are ruled by their hormones. Be it boy or girl or something else, they want to attract attention from the opposite sex (and sometimes the same). They will think about this all the time and base their actions around it, with …

tvtropes.org

Dumbass Teenage Son - TV Tropes

A standard sitcom family usually has one or more of the following: the reasonable mom, the obnoxious little brother/sister, the "misunderstood" teen girl, and the stupid loser dad. Of course, to round out the nuclear sitcom family, there's one …

tvtropes.org

The Peeping Tom - TV Tropes

The Peeping Tom is a character who gets his kicks from non-consensual voyeurism — spying on others in explicit situations without their permission or knowledge. Peeping Toms are often driven by a fetishistic urge, deriving pleasure not just …

tvtropes.org

 

[owotrucked]

"toddler minds" lol

Let's imagine that the MC's mind is specialized in decision-making. Then the cheerful proactive idiot friend would be specialized in observation.

The MC only sees his friend's underdevelopped ability to make correct judgement, while the friend only sees the MC's underdevelopped engagement with the world.

Give the friend an intense love for interacting with what he observes. He can have attention trouble: A laser focus concentration on things at hand, but difficulties to "direct it consciously". For instance, if he's in the bath, he can't help but have his attention pulled towards the sweet giggling voices across the barrier. He's painfully receptive to the splashing sound and how they tease each other size breasts.

Because his mind puts so much juice on observation, he gets nothing left to assess the consequences of his acts in the future, or reminding the mistakes of the past.

For that moment, the external world is their entire world. And to be alive, they must act on it.

For them, action always beats inaction.

Famous last words "Hold my beer."

That's my take on the dare-devil archetype for rash decisions

 

[Nane]

I immediately thought of Hide from Tokyo Ghoul. I think the purpose of these characters in a story is to make a stark contrast between them and the angsty MC, while being the comic relief.

How to write one? I plan to write another story with a character like this, and my plan is to take reference from someone I know who is cheerful and chaotic. Combining it with the large archive of examples from existing fiction, I think it will be a fun character to write.

 

[Agentt]

write them stupid

Stupid makes brain hurts

all of those little things they do come across as distractions from their own issues

Also, this hits deep

 

[ArcadiaBlade]

Eccentric BF Side chars are mostly the type to give observational outlook in the third person view. You don't have to make them act stupid but they are mostly shown to be like a sunshine, opposite to the MC who usually acts negative. To play them right, your MC must have a weakness for them to compensate as they act as a barrier breaker to progress a plot to the direction you want them to be.

They are mostly seen on harems that have an MC which acts nervous to the girl they like as they aggressively break the barrier to create a connection between the love interest and MC.

They are also made to give inspirational speech to motivate the MC that goes into depression as they light up the candle in their hearts.

Basically like a lighter to a candle.

 

[Motsu]

Have a best friend. Build your foundation from your real life inspiration.