What is this verb form? 見せっこ


I am reading Hunter x Hunter, and the two protagonists (friends, and kids) are
given cards that they are not supposed to reveal for the duration of the game.
They start talking and they exchange a bit of information and then this is
said :

![bubble](https://i.stack.imgur.com/xhtLo.jpg)

`せーので見せっこするか？`

Then, they proceed to show their cards at the same time (saying せーの).

I understand that one asks the other to show the card but I am unsure as to
what is this form (is it a contraction of sorts?). Does it comes with a
particular nuance?

Thanks!




「[連用形]{れんようけい} of a verb + （small っ） + こ」 = "performing the same action
to/for/with one another"

「見せ」 is the 連用形 of the verb 「見せる = "to show"」.

「こ」 is a suffix that sort of functions as a nominalizer while giving the verb
a meaning of doing the same thing among two or more persons as a competition,
game or just fun.

See こ[接尾]1 in :
<https://kotobank.jp/word/%E3%81%93-493368#E5.A4.A7.E8.BE.9E.E6.9E.97.20.E7.AC.AC.E4.B8.89.E7.89.88>

"Show me yours and I'll show you mine."




「[連用形]{れんようけい} of a verb + （small っ） + こ」 = "performing the same action
to/for/with one another"

「見せ」 is the 連用形 of the verb 「見せる = "to show"」.

「こ」 is a suffix that sort of functions as a nominalizer while giving the verb
a meaning of doing the same thing among two or more persons as a competition,
game or just fun.

See こ[接尾]1 in :
<https://kotobank.jp/word/%E3%81%93-493368#E5.A4.A7.E8.BE.9E.E6.9E.97.20.E7.AC.AC.E4.B8.89.E7.89.88>

"Show me yours and I'll show you mine."

