because its the flappiest part of the vagina it is the optimal spot for a raspberry: when one presses their lips against the labia majora and blows air making a sloppy wet sound.
Me: hey Chris, I clam flapped your wife last night...
Chris: "oh yeah, I was gonna clam flap her last night too but she was on her rag. BURN!"
Chris: "oh yeah, I was gonna clam flap her last night too but she was on her rag. BURN!"
by Naterball, Aimdog, & Briggs October 15, 2011
Get the Clam Flapmug.