According to the artist, she's kissing him, using what is apparently a vestigial mouth (or possibly beak) on the bottom of her.

Looks more like she's forcing him to eat her ass O_O

face full of alien wing wong

disgusting

It's a head crab get the crowbar.

I hate to think what's going on if that's NOT her mouth on the bottom.

Apply directly to the forehead

New meaning to face rape. Now with added bald shine!

also he has a very long stomach