When someone behaves ridiculously.
Also, when one is jumpin they can be referred to as "on the moon with Mike Busto"
And if someones jumpin you tell em to look up.
"yo shut up"
"man your jumpin so high when i looked up i seen you on the moon."
"yo fuck you"
"look the fuck up."
OriginatedGlasgow/ any poor area with drink problems
Jonny " Theres a tramp over there. Come on lets get a jump in.