Yeah, the first time I smoked salvia it was from a kaos bong like the one in yer picture thingy (correct me if I'm wrong about it being a Kaos), and, like you, I couldn't stop laughing. But it wasn't at anything that I actually thought was funny. It felt like I was possesed by something making me laugh as hard as I possibly could, so hard in fact it fucking hurt and wore out my damn throt.
It's a facinating drug, it really is. Like someone said earlier, no one describes it as "great" or whatever, either they hate it or they admit that, if nothing else, it is extremely facinating to look back on your trip and to see people on it and to discuss tripping out on it with people.

Sincerely: Glowis