To pump one's cavernous tissue.
Scott was hiding in the bathroom stall, buffaloing all during math class.
Connecting to a unlocked wireless network that is not your own without the knowledge of the wireless networks owner.
A: I couldn't pay for internet at my house, so I drove down to the coffee shop, parked next to their back door, and buffaloed their internet.
B: Yeah, I've been buffaloing from my next door neighbor for the past year.