Wario would definitely do that shit but the problem is he would also like his ass eaten in return

Captain Falcon, Dr. Stewart, Billy, Jody Summer, Octoman, The Skull, and PJ all eat ass

Metroids

I believe Luigi probably would if you asked him nicely enough and Yoshi would do it but only to clean his friends up after an egg prolapse or something. Yoshi's are non-sexual creatures.

Z (yes, unfortunately he does it to his pokemon)

Mr. Mime

Tharja

This specific version of Peach and she wants it done RIGHT

N (and he likes to do a little nibble. It hurts a little but just let him do it)

Queen Bee's Servants and Mario that one time (canon)

Lanky does it to himself and it makes everyone really uncomfortable

Every single character in this game

Reaper, Soldier 76, Reinhardt, Bridget, Orisa, zenyatta (Usb c)

Papyrus

Crunch Bandicoot (+ finger)

The Arbiter

Makarov

Spy (canon), Heavy (on Sacha), and Demoman (both ways)

Telma, Oocaa

Ayla, Frog

Goompa

Blue Sprixie, also a side effect of the cat bell is that the user might be tempted to groom themselves

Raven Beak

Gil, Krobus, Demetrius, Shane, Abigail

Maxwell, Wickerbottom

Cole

Chris, Wesker, That one big ass monster with hella tentacles in the lab

Ada Wong, Mendez, Luis

The mega man on the cover art

Dante, Trish

V

baldur (in olden times), Enzo (special occasions), Rodin (everyday)

Klungo, Humba Wumba, Gruntilda (sexy version)

Timbur, The Clock, Wizpig