Have done a double a couple of times. Had fun but after each one I didn’t quite feel it was worth it. I’m pretty much a one shot in an hour guy, so that meant I missed the opportunity for a complete experience with one of the girls. It also meant two hours worth of resources went into one hour of time, so that meant one less enjoyable hour. Twice, I have done a back to back – one hour appointment with a girl, one hour off, a second hour appointment with a different girl – which I liked better than the double.
So, worth a bucket list item. Make sure the girls are compatible. But for me, I like to have two hours. If I ever do it again, I will shoot for complete height differences, something like 5’0” with 5’10”.