having been pinned to a wall, table, couch, floor, bed, and car hood, I'd really like to vote for the couch or floor. Walls only work if you're both *just* the right height, otherwise there's slippage. the table and car hood both end up being a bit short, so there's legs flailing. the bed...eh. it's a bed. I mean, one *can* be pinned to it, but it greatly ressembles non-pinning. couch is good cause of the straddling factor, and the floor is nice cause there's usually room to roll around and/or shift into more comfortable positions.

yes, um. that's about $1.30 of my 2 cents.