A form of foreplay in which one gives the male partisipant head while tugging on his pubes (jellyfish tentacles) and licking his sac (the squishy part of the jellyfish)
Mark: Dude, my girlfriend
gave me glorious head last night
Rob: Duuuuuude, did she finally agree to give you jellyfish sex
Mark: Heck yes!
24 марта 2011