He comes over, "Who's sitting here by themselves in teh stall" and jumps up and grabs the framing cross bar up high to pull himself over for a look.
I'm standing up and trying to pull down my shirt to cover things up. Luckily for me the lock on the stall gives way when he's trying to climb up using his feet. It slams in on my, knocks me back down on my butt onto the toilet seat, he falls off, door bounces back shut. That gave me time to get my pants on, and he was very apologetic when I came out.