This happened to me even with a blunt (and blunts are damn harsh!).
I took a hit of this blunt and thought the blunt was messed up or something and I said "hey, I didn't get any-" but when I talked, a lot of smoke came out of my mouth and then I said: "holy shit that's smooth!"

I think it was cause it was a wet blunt that made it smooth?
It was made by giving a cigar a blowjob in order to deleaf it and shit, yea you know what im talking about.
Moist = smooth.