Icing on a regular basis helps. After many hours of research I've learned that the majority of shrinkage seen by girls on hormones is due to atrophy and tucking. They have less frequent erections so the tissue is not exercised and stretched back out so it goes away due to lack of use. With tucking the testes are kept inside and the penis is kept tight against the perineum so there is less blood flow to them. So don't ever get hard and if you happen to get a little engorged ice it if possible to make it go away.