To revise, especially cramming.
"I've really got to bone up on these maths problems."
Slang term for getting stoned and masturbating at the same time.
I was bored and had some weed, so I found a couple of porno mags and started to bone up.
The past tense of bone up, meaning literally to have an erect penis, or figuratively to be aroused, excited, or enthused.
Damn, girl, you got me all boned up, and now I gotta tape it to my leg.