Cats metabolize THC in a different way than we do. The effects are slightly harsher [as in acting drunk rather than high, and more fatigue and confusion] and much shorter, with the THC getting out of their system within 24 hours. Contrary to popular belief, they do not remain stoned for the rest of their lives.
However, it is actually better for a cat to "absorb" it through the exposure of veins on the ear, rather than inhalation or digestion. Digestion is actually the worst way for cats to process anything.
However, most cats and dogs don't really enjoy the experience, as it isn't as pleasant for them as it is for people. I wouldn't toke up your cat anymore, plus you said you couldn't tell if he enjoyed it. He probably didn't. Plus, it's really hard to focus the smoke on the internal ear structure without it being inhaled. Despite the fact that marijuana hasn't been shown to be detrimental to human lungs [again, contrary to popular belief], it may still be to pets because their organ tissue genetics are different than ours, and they don't have proper THC receptors in their brain like we do. Because they process it so fast, it can be taxing on their system. Therefore if you just had to smoke him out, the less often the better to give breaks between the work his/her body is doing.
Overall, your cat isn't in any major health risk right now, but I'd suggest you'd stop smoking him out since he didn't like it. You wouldn't pin someone down and force them to inhale stuff would you?
[Vet student btw, ask if you have anymore questions. I researched this because one of my good friends frequently smokes out his cat, and I was slightly concerned. Plus I was curious.]
Yeah, it's hilarious to smoke cannabis with pets, but I wouldn't do it often. Although, I've read most of the harm cannabis smoke causes is due to the temperature of the smoke, so it should be cooler after leaving your lungs. Remember cats have much smaller brains... so one hit of second hand smoke is enough to make them stoned lol
It's probably a bad idea, especially if your cat doesn't seem to like it. Just give the kitty catnip or something. It seems that the main danger from marijuana ingestion for cats (judging from a link someone else posted in this thread) is that it can cause them to vomit, and that, combined with marijuana-induced lethargy, could lead to choking and suffocation. I'd say that there probably isn't any research into long-term effects of THC consumption on cats, so no one can say for sure what the long-term effects might be. If I were you, I wouldn't chance finding out with your cats.