Yes, all the time. If I want him to try something, and he's not sure about it, I just plop some sour cream or ketchup or jelly down on his tray and say "dip dip!" He loves it! He doesn't make as much of a mess as I think other kids might, but he's careful not to get it all over. If it gets on his fingers, he holds his hand up and says "eh eh" until I clean him off.
I'd kind of forgotten about hummus. I need to give that another try now that he's so into dipping. Thanks!