"Oh yeah, Mark! Look at you taking care of your nasty sister, giving her what she needs." I began grinding faster and he began bucking his hips into me.

"Hold on little brother," I told him. "You get me off first and your big sister will give you a treat."

Mark grunted and closed his eyes trying to hold himself back. It wasn't easy as I was bucking like a fucking bronco. I took one hand off the bed and twisted my own nipple, the jolt of pain took me over the edge and like last night I through my head back and wailed like a siren I was cumming...