putting it back is the key, I cum in my wife and sister in law's cups all the time. Love the idea of my cum pressed up against them all day and the thought that once it gets warm they will smell of sex all day and not know where it's coming from.
I love this. I do this to my wife's panties all the time. Isn't it so fucking hot that she is wearing your cum around all day and doesn't even know it.