A flying fuck. Can be used as a way to ask for sex.
WARNING// Be careful asking for seagull. They might think you are calling them a flying fuck. You will definitely not get fucked if you do that. :)
Person 1- "Hey Justin, do you wanna come over to my place and seagull?"
Person 2- "Yeah Selena, that sounds great!"
"Ugh! You are such a seagull!"