well just drop your pants.........er..... i mean ...uh...........
Actually if you want to break through that kind of mental barrier go to a dance and make sure theres lots of really close dancing. After a while i think he will get the picture, especially if you kinda work your way closer to him..does that make sense?( i dont mean that in a sexual way, i mean you initiate dancing closer and closer)
That would probably be the easiest situation because physical contact is a given with dancing. So that whole thing is outta the way.
Any other way i can think of would be easily dismissed as doing a friend thing. Like going for coffee or a movie, or to the park, ect.
Then you can pull one of those super close face sliding things like in the movies. .....not grabbing his face and raking it on the concrete, i mean go from having your head on his shoulder and sliding your cheek along his until you are face to face at the end of a slow song, even get some freeby side lip contact. If he dosnt figure that one out i think you should rake his face on the ground.