southern english dialect term for a confined pathway, often used for sexual activities and illegal substance consumption. Or as a hang out for chavs. It can also be used as a shortcut through parralel built council estates, if you've got the balls. (it's an alleyway pretty much)
Toby: Cor thom, do you wanna go down the alley for some summin summin?
Thom: No i'm going down the twitten to fuck some german hookers and smoke some crack