http://mjmcompany.com/petsilk-finish.htm
Click on the link and scroll almost all the way to the bottom of the page. On the right hand side is stuff called TopKnot Gel. I used to use this at work. I am not sure if it says to wash out right away but I use it and I dont wash it out right away. It doesn't harm anything to be left in between baths.
Dont use human gel unless you find some made for babies, THe alcohol content is way to high to use on dogs and might dry his hair out really bad, plus if for some reason he gets wet, it could get in his eyes and that isn't good either.