what who said you just lay there lol
i've done it back in my early 20's. They give you free gatorade and make you chill while the plasma separates. they draw blood from you, and that sample goes through this machine that makes it jello. it takes a while to extract the plasma though. thats the wait. but your not waiting while a needle is inside you lol
as for pain, it just like any other needle procedure. i used to go to biolife here in texas and they paid about 50 bucks a session but then again im talking back in 2005 lol