I had to laugh at this. I'm INFJ and two of my closest friends are also INFJ, our conversations are always like that. We talk until our tongues bleed but it is constantly going off topic and we have to explain EVERYTHING with painstaking detail, hehehe.
I also have a close friend who is ESTP, and he gets what my friend calls "the ticking face" when I talk to him. He will be into what I say for awhile, but when I start going off on one of my long, descriptive tangents he starts glazing over and his chin starts going slowly down into his chest, like there's a clock ticking down inside his head telling him he can only take so much more before it explodes, lol. Eventually he starts looking at other things in the room and responding only in grunts, then I pretty much know it's my cue to say "Dude, am I killing you?", hehe.
With my NF friends, we can talk for hours at a time but always leave the conversation going "Damn, too bad we have to cut this off, there's so much MORE I wanted to talk about!".
It's sick. But cool!