There are enough curves there for Jack, given his general abstinence from anything curvy in recent months, and it's not long before his hands are tugging Spike's t-shirt out from his jeans and sliding up beneath the fabric, over skin that feels familiar enough in its coolness but oh so different in shape. They slide up to cup those small but wonderfully yielding breasts, palms rubbing lightly over the nipples to make them pebble, and then he's pulling back enough to shove the t-shirt up and off so he can get a good look at Spike's changed form, grinning like a cat who got the cream because, hey, that's what it feels like!