I use a glue stick and after the quilt is done it just washes out :)

I've tried diluting it with water in a spray bottle as others have recommended, but I couldn't get the amounts correct. I like the idea of standing over it and dribbling (sounds so creative, doesn't it?). I've got a quilt on the floor now that I'm going to try it with.

You can also use 505 spray glue. This works more expensive but easier and quicker, although you need a well ventilated room. Elmers school glue is especially made for use with children hence it is washable and should disappear when the quilt is washed. Other glues do not have this option