DiabolusInMusic
Functionless Art is Merely Tolerated Vandalism
You've mistake balance with "not able to move due to a strap that doesn't slide". Throw a cheap nylon strap on there. Those mofos will slam their headstocks into the floor.
The angle at which the OP plays helps a lot as well. If you wear your bass at "proper" height, it should fall right onto your lap for proper sitting position, the bass sits at a much more level resting point, which makes it head to the floor.

