(Hope that title makes sense:^)

Yeonjun

You- Randomly slap his butt.

Him- Pinch/Grab/Squish your cheeks.

Soobin

You- Poke him

Him- Cuddle you

Beomgyu

You- Bite him

Him- Bite you

Taehyun

You- Fake sleeping so he'll wake you up.

Him- Playing footsies with you.

Kai

You- Pretend to kiss his mouth then kiss his cheek.

Him- Play with/Slap/Touch/Wiggle your butt.