Welp, I've managed to avoid 4chan until now, and now I have confirmation I haven't been missing anything. Summoning demons for sex? Well, if succubi were real, it's a sure bet people would be doing just that.
As to whether the folks on that thread really believe what they're spouting, I don't have an answer either. Probably at least some of them are just playing along out of amusement, or to be "in" with the group.
Thanks for letting me have a glimpse of 4chan, Sketchiii. I doubt I'll be back; I can get better laughs over at cracked.com.