Batty means bum and flap usually means the cheeks. Its an urban British slang and for some strange reason others have gotten a different meaning of it. Like how the word faggot which is actually a name for a type of food some how got converted into a nasty insult towards homosexuals by people. Usually it is just used because its funny and more polite than saying arse cheeks.
I will shove that up your batty in a minute. Explanation: I will shove that up your ass - Used when somebody is annoying you with something.
My batty flaps are flapping because I just farted. Explanation: My bum cheeks are shaking from my farting.
My batty flaps are flapping because I just farted. Explanation: My bum cheeks are shaking from my farting.
by Flapping Batty January 24, 2016

by greenblazer April 4, 2019

by Solo-/:// March 26, 2013

by Leon d GOD April 21, 2018

A gigantic arse intruding dildo, nothing like you have ever seen. The only thing that matches the length of this beast is it's girth! It's what can only be described as a arse destroyer. Only the most accomplished and experienced can even attempt the task of conquering the batty rattler!
by Jonny and Steve August 30, 2018

by greenblazer April 4, 2019
