Trying a combination of these worked for me.
1. Freeball as much as possible.
2. Gently massage and then stretch your ballsac daily for 5 - 10 minutes.
3. Vacuum pump your ballsac individually 2 - 3 times per week. I use a 2-inch diameter tube which gives me room for width expansion, but most importantly for lengthening as the sac is stretched further into the tube. Done right this is a very comfortable and easy passive activity.
Previously, I had a very tight almost invisible ballsac. Today, everything hangs loose, full and matches with the increased size that I’ve gotten in my dick via PE.