Just chill and have a good time. Try not to think about anything except how good you feel and how beautiful things look, etc. If you do it with a few close friends in a secure environment, you should have no problem. I have never had a panic attack or anything and I usually smoke in public places or places where I might get caught (side of a road or in my friends job after hours) because there are no parks or secluded spots near me. It might be better if you don't get drunk before you smoke. I usually like to smoke a lot and then when the cotton-mouth kicks in I have a few beers/shots, whatever. Beer also tastes better when your stoned.

Just chill with your friends and listen to some mellow music and have a good time. Don't worry about anything.