Well, I don't really think its a good idea to get him ripped the first time.

I did this with my mate, and gave him about 2 big bowls in a bong and he got so fucking stoned he fainted about 2 minutes after clearing the last hit!

It effects some people differently, I would just roll up a nice fatty L between both of you and 3 toke traffi it or something, you can't not get stoned from that.