I roll generation joints from roaches too...those are wonderful things!
Don't slip too much out or they are going to notice man, limit to 3-4 enough to roll a decent smoke for you. (don't smoke out your homies on stolen stash, that's tacky) I promise ya he will know just about how many joints he can roll out of his jar at a glance so pick selectively. (plus you know roach joints are more potent anyways so you'll need less)