Created in 1980 by the original hackers of the Bulletin Board System. l337 is a variation os the word 'leet', which itself is derived from the word elite. Elite has been used in the past to designate a group of users as belonging to a higher social echelon than other users. The term Elite was gained from the classic game Elite.
When your woman (or man) kicks up their right or left leg during sex or another intimate moment and it remains there. It either expresses extreme orgasmic joy or it means that you are rancid awful at sex.