I know this is very true with our own doxie Duke! He has a time staying in my lap unless I am in my recliner with my feet up. He's longer than most doxies I've seen, which is fine, but not so good when he's trying to find comfort in a human lap.
He tends to slide down unless he is held, and that gets tiresome. Fortunately, our couch reclines as well, so there's plenty of safe laps for him to flop down on.
Dachshunds . . . you gotta love 'em!