This happened to me a few times. We changed positions and he tried to go back in and couldn't. I reached down and I was bone dry. Maybe that could be your problem. If so, easy solution... lube.

Maybe it's not a problem with lubrication. Maybe you're just tensing up for whatever reason. If this happens, see if you can just easily transition into foreplay or him giving you a massage for a while and then go back into sex when you feel you can. It might help you relax