High waist jeans, or high waist shorts, having mess poured in dead centre so it flows down and the flow gets split by the crotch of the trousers/shorts. Ideally while clothes are otherwise clean and dry, so we get to see the wetness of the mess wet through the material.
Have a massive satin blouse fetish, Watching a lady all dressed up then getting wet, messy and ripping the blouse apart in a sexy way of her beautiful body.
I've got a fetish for knees! Specifically It's when the joint is flexed, so for instance when a girl kneels or squats. Add mess to that and I'm in heaven.