when a female is riding a bike, usually over rough terrain, and she slides the bike seat into her VJ. this will result in a smile on her face and an odd musk on the bike seat
Colleen "Nice new bike Vanessa"
Vanessa "thanks Coll"
Colleen "hey where's the seat, and why are you smiling so much?"
Vanessa "oh I'm performing a Bicycle smile, lets find some rougher terrain"