A euphemism used by 90's Australian primary school children to refer to anal intercourse, usually with negative connotations.
Boy 1: oi where's Ricky? he's missed school for weeks.
Boy 2: nah yeah I heard he got a bumjacking by the principal for stealing deano's tuckshop money, apparently Rob from 6A saw him in a wheelchair on the weekend.
To heavily drool on the end of a cigerette, most possibly one you are sharing with a friend or work coleage
"OMFG!! Oh my fucking God, Poppy! Look how much you've bumsucked it! Your skanking me! Your skanking me, mate! You've gotta pay me back for all of that! That's 17p please! You're twisting my melons, man!! Look how much you've bumsucked it. Quit skanking me!"