Make sure you clean up good afterwards. I always had a towel, body wash and a water bottle with me when doing my jelqs. Wait until you get all the extra skin and get a pimple mid shaft, that's a fun thing to explain to a check. Just listen to what your body tells you, push until your body gives in and let's you have the say in how far you stretch or expand. Rest is needed so don't ever feel bad about it.