they want you to think its vanessa/dan/olivia but if you re-watch the promo tripp is at the end saying well that was interesting and serena is sitting around a bunch or booze and the plaid shirt id the threesome is nates so...
dan/olivia/vanessa!
first dan kisses olivia, then olivia turns to vanessa and kisses her then (DRUM ROLL) dan kisses vanessa! O M F G G!
then the next scene they show is the 3 of them lying in bed, sleeping!
The 3 people involved in the 3some was Vanessa , Dan and olivia. What started off as a drunk fun event then turned into a shock turn(MUST RESIST SPOILER TEMPTATION)
