3rd round sex

So I wasn't sure if other people get dry after the 2nd round of sex because I could be soaking one minute and lose it all the next even though I'm so turned on and I'm not sure why. Obviously I will do some research on this but I was wondering if this is common for other girls and other than lube, what might help? It normally only happens after we've had sex twice within an hour and go for a third but I'm basically dry.