Several guys stand in a circle around a biscuit (possibly a wheat digestive). They all begin to jerk off, ejactulating onto the biscuit. The last person to cum, consequently, has to eat the soggy biscuit.
A limp biscuit is the mathematical term for an infinity shaped curve, commonly misunderstood as a lemniscate. It has been rumored that the band Limp Bizkit got their name from the idea of being infinite, so they wanted to use the mathematical term for the symbol. But sadly the creators of Limp Bizkit did not have the greatest spelling skills and the word biscuit was misspelled in their name. The term limp biscuit originated from Jacques Bernoulli back in 1694.
Person 1: "What do you want your team name to be?"
Person 2: "Limp Biscuit!"
Person 1: "What did you say? Lemniscate?"