(This was a custom commission but no names are used) Sis needs kissing lessons but she would NEVER give her own brother a kiss on the lips. Instead, she’s heard that the human anus feels just like a real mouth and that practicing on your butthole will yield a decent result without really having to kiss you. You’re confused at first, but you pull your pants down and let her go to town. Sis begins to shyly give you little kisses and soon moves to practicing French kissing. You love sibling kissing lessons so much that you ask to switch places and soon find yourself kissing the set of lips between her thighs. You’re skilled with your tongue and sis quickly climaxes. She’s a little embarrassed that her own brother gave her an orgasm, but at least the two of you never kissed. That would be unthinkable.