In alpine skiing, being in a position where one's center-of-mass is shifted toward the tails of the skis instead of toward the tips. Results in reduced control, adaptability to changing terrain, and ability to make a full turn.
The curious phenomena by which men traveling in the back of large jostling vehicles (busses, vans, ect) tend to achieve spontaneous erection due initially to the jostling of the vehicle and then secondarily to the jostling of their own wood against their legs and/or pants. This erection can often be relieved only by extrication from the back seat.
When a Sneakers O'Toole look-alike has a cab service from school to the club. Sneakers O'Toole then lets every chick in his car drink, and inevitably, they spill some cranberry/vodka on his seat. Sneaker O'Toole will get the drink stain confused with a Virginia Slim stain.
Sneakers: Yo man, I'm gonna have to run by the cleaning section. Someone spilled some shit in my car. Now I think I have the Back-Seat Stain
Grinnell: Actually, I think it may be a Virginia Slim stain.
Sneakers: You know... that may actually be what it is.