'Bum-ish' Meaning something is not up to your or others standards, and if something is 'not good' or 'bad'. It has been used alot in the younger generation as sort of a light way to let out your inner feelings. Or in other words, a censored swear of sorts. This could also add comedy to the situation your in making the thing that's bumish less, well, bumish. As it uses the word 'bum' which may be entertaining or funny to the younger people.
You could use it like: "That test sheet was bumish" instead of: "I didnt enjoy that test sheet." You would not say: "It was so bumish.", just: "It was bumish."
An extremely unfortunate final moment during the climax of one's porn-accompanied masturbation session, in which the viewer of said pornography experiences their orgasm at the exact same time the cameraman gets an all-inclusive shot of the guy's ass for a solid 5-10 seconds
Guy 1: "Hey man, you don't look so well. You doing alright?"
Guy 2: "Dude, I just had the most humiliating bumshot..."
Guy 1: "Jesus...that's just bad luck, man."