Simulated oral sex. Or any public head to groin action. Coined by Ryan Seacrest in regards to Adam Lambert's AMA performance.
Also see: Pink's 2004 Billboard Awards performance
and Derek Hough and Joanna Krupa on Dancing with the Stars.
1. "Man, he knocked Tom Brady on his ass!"
"Yeah, it was a great sack, except for the part where he totally crotch snorkled the dude."
2. No Madonna performance is complete without a requisite crotch snorkle from the dancers.