If the stuff was good enough to get your friend wasted off one hit, you probably don't need 3 or 4 hits if you're a newbie.

Some people think their weed is laced, but it's a misconception. First of all, it's hard to lace bud with anything else because you can see it. Also, good coke is more expensive than weed, so nobody would waste their coke to lace the weed.

Really good bud can expand in your lungs, which causes some people shortness of breath. And the shaking could just be from a good body high - do you also feel numbness in your head and body?