I've patched hundreds of jeans. With FIVE sons, I have practically re-made several pairs. "But mom, they are my favorites!" I use a piece of discarded jean, put it underneath the hole, take off the big wide surface of the machine to use the narrow base that will fit up the legs, then do a wavey line thing to attach it.
Here's a good story. One of my stepsons left his laundry in the washer, so I dried it, and was folding it when I noticed a huge hold on the front, near the base of the pocket. So being the mender that I am, I promptly mend the hole. As I'm folding the jeans, my other son comes into the laundry room and laughs! He said that my stepson had just bought them. He bought them that way. So replied "No one is allowed to show their underware through a hole in their jeans in OUR house!". It's been a year now, and my step son has never mentioned the mending job. And he continues to wear these jeans. Sara