Glory Hole.

Whoooooa, there! What the fuck is this!? Hey, you in the next stall, what the fuck!? Why have you pushed your boob through the hole in the cubicle wall?

I'm glory-holing you. Just go with the flow.

'Glory-hole'? What the hell is that!?

It's an anonymous sex act. People put their junk through a hole in a public restroom cubicle wall, and y'know, they get it on. It's sexy.

It's really not sexy. I mean, it's really, really not sexy to suddenly have a boob emerge from the cubicle wall - while I'm sat here pushing out a shit. Oh yeah, and did you forget that you're my sister? Sisters don't really do that kind of thing.

See, I was thinking that. But then I thought, 'yeah, if I'm ever going to have sex with my sister, it really should be anonymously through a hole in a public restroom'.

Holy shit, you really thought this through. I actually hate you.

Of course I thought it through. I mean, I was intending to poke a couple of fingers at you through the hole. Y'know, to offer you a little fingerbanging. But, I don't know, it just seemed kind of rude to go straight into offering you something like that. You're a classy girl, plus it's pretty safe to say that I have some fantastic tits happening on me. So I decided in the end to try and get you going with giving you a view of the old assets.

I'm really glad you consider me classy enough to flash one of your udders at me, in an attempt at a weird, incestuous love affair. I'm really not interested, but thanks anyway. Now I'm just about finished doing what I came in here to do, so I guess I'll see you back in the car. I can't wait to get on with the rest of this, the first day of a two-day road trip with you sat next to me.