Green’s Dictionary of Slang

bog v.2

[? SE boggle (one’s eyes)]

(UK juv.) to stare at in (what is seen as) an aggressive manner.

OnLine Dict. of Playground Sl. 🌐 bogging (1) v. [...] (2) looking at someone in an offensive manner (question is posed as a threat). eg ‘You boggin’ at me?’, Question usually in accusatory manner in same context as ‘you got a problem?’.