"S.E.X." is the first single by Lyfe Jennings from his second album The Phoenix. The song is about young teens losing their virginity from pressure. The song features R&B singer Yolanda "La La" Brown."S.E.X." debuted on the Billboard Hot 100 chart at number 99 and slipped off just to re-enter the following week again at number 99. It eventually peaked at number 37, making it Lyfe's (and Lala's) most successful single.