SouthernLady:
Yes that is what I am looking for to read in the library.
Ahhhh, the idea of a male spankee being required to affectionately kiss the bare derriere of a female who has just spanked him, or is about to spank him, or perhaps has even merely been a witness/assistant to his spanking by another feminine disciplinarian, I find that a highly appealing concept.
Unfortunately, I've never written about it myself.
Okay, just kidding there...
"Drying Off a Derriere" (marital play--short)
"Showing Him Who's Boss" Parts #2 & #4 (marital and otherwise, #4 includes some simultaneous)
"Faking It" (included as part of femdom sex-play)
"Smack Exchange" (marital game--short)
"It's Not Fair!" Letter #2 (game involving teenage and older-preteen children, near-simultaneous)
In all of these, feminine bumcheeks are bared for those sweet "smacks."
Also, near the ending of Smeple's "You Bet Your Ass" serial (Part #8) there's included a brief bit of M/FF seat-smooching, a man kissing the bottoms of two of his wife's friends who've helped her chastise him, although it's over clothing.
I hope these suggestions will help you...

--C.K.