If you train seriously with weights, will you keep your strength and muscular size gains if you simply stop training? You’ll have to maintain yourself at some level if you value your gains.
With PE, some part of gains (if you get them) apparently are elastic in nature. With cessation of PE the tissues can retract to some degree. However, enough veterans have stated that their gains have remained well after stopping PE (two years or more). The key to keeping most of what you earn with PE is to gradually taper your workouts down over a period of weeks or months. It sure would not hurt to then stick with a light maintenance routine. For instance, a bit of jelqing a few times a week could go a long way to maximizing the vascular performance of your dick. Jelqing also seems to help the penile veins appear more defined—something a lot of guys appreciate.