I remember a long time ago when shrinkage after a workout was considered good because the retraction means you have done some work - like, if you didn’t do any stretching there would be nothing to retract against if you catch my drift. But now we have things like traction wraps and ADS to help keep the tissues extended after a workout.
Also, if your skin is tight naturally then it is normal to feel the stretch there before you get to stretching the ligs or tunica. If the skin is tight then it will naturally take more of the stress assuming your grip is ok and the skin is not pushed forward when you stretch.
Again also, if you are dry jelqing and getting skin stretching then wet jelqing using something like KY jelly or vaseline would be a good option.
Good Luck, any more questions just ask.
SS4