Q.When and how should I prune a sweet bay magnolia
Our sweet bay magnolia is pushing up against home and fence. The tree is more stringy than “full” and I am thinking that pruning the tips of the branches will force growth next spring into the center of the tree. Any thoughts on this would be appreciated.

Magnolia can be stressed by pruning, keeping pruning to a minimum.
Here are a few links that will help you.
https://www.gardeningknowhow.com/ornamental/trees/magnolia/sweetbay-magnolia-care.htm
https://www.gardeningknowhow.com/ornamental/trees/magnolia/pruning-magnolia-trees.htm