While having sex on a beach a man pulls out his penis, sticks it in the sand then rams it back into the womans vagina. The result is generally a loud high pitched shriek (ie. Screaming Seagull) as well as some chaffing.
Bob and Sarah were going at it on the beach last night and it sounded like he gave her the screaming seagull.
The screaming seagull is when a man and a woman are having sex on the beach then the man pulls his penis out suddenly and dips it into the sand before putting it back into her therefore making her scream like a seagull.