I am the oldest of 5 and my parent(s) often did not have an adequate vehicle to safely seat all 5 of us since they took up the front seats. So the usual configuration was to have one of my sisters sit on me and my brother's laps. They were very thin girls, and sadly they're bones would grind painfully into my crotch in perhaps the worst possible way every trip we took. i would try shifting them to one leg, or have them sit on a jacket or something but it was just pure torment regardless of what I tried. It has haunted me to this very day, every lady I've dated has possessed an ample posterior to avoid flashbacks to such trauma.