My girlfriend and I occasionally cover each other in chocolate syrup. I think she didn't care for it so much at first, but is beginning to really enjoy it. She's commented that it makes her skin soft! (It does!

We've also taken bubble baths together with her wearing something in the water. I once had her wear a shirt and long pants, and she really didn't enjoy that; she said the pants felt heavy and uncomfortable, while wet. But she's also worn knickers and pajamas in the tub, and she's enjoyed that.
I'm greatfull that she's at least willing to do these things with me. If she didn't. . . well, I'd be upset, but I wouldn't love her any less.