when you go in so deep on a girl, her lips come out and tickle your balls like a pair of frog legs. She usually needs to be kinda loose or have some large lips if you know what I'm saying.
Man that bitch definitely had some frog legs, that shit was straight tore up
When your legs finally start to warm up after a morning of skiing or snowboarding. Optimal athletic performance is usually achieved when you have your "frog legs" on.
Skier 1- "This powder is awesome!"
Skier 2- "Eh, give me a few more runs. I don't have my frog legs on yet."