Same problem here. This is what I do. To start, as Lord Harris mentions, use a good lube. I prefer aveeno skin lotion (thicker than water based lube) Anyway, I get a good overhand grip with my right hand at the base. I then take my free left hand and make a quick tug and release at the excess skin near the base just as I start the first jelq stroke. When the right hand nears the gland I quickly use the once free left hand to get a strong grip at the base and finish the first jelq with my right. I then use that now free right hand to make a quick tug or pull on the excess skin as I begin the second jelq with my left hand. There is no real hurry as long as one hand has a tight grip at the base before the other hand finishes the stroke. It’s tedious but if don’t continuously tug away the excess scrotum skin before each stroke, I just end up pulling skin right up along with my hand. So, I don’t think you are doing anything wrong but this adjustment will allow for a smooth and effective stroke. Have to use two hands, sorry.