I think lap-sitting is a lot more enjoyable for the person whose lap is being sat upon, as opposed to the actual lap-sitter. It's a dangerous and uncomfortable position to be in. Like someone else said earlier, you are always worrying that your heads gonna knock your honey in the teeth. When I ride, I usually end up stooping down with my head against my husband's chest. Not too comfortable. I much prefer to ride on my own.
(I don't know why I used this smiley, I just felt like it, I guess.)