We had the same problem with DS. We've got one of those lounge chair type support things for him which works brilliantly. He lays back and has a good kick and a wiggle. It makes it so much easier for him and us can he can relax and not feel as vulnerable and we don't have to worry about him slipping out of his hands. It also means that his body can be immersed in the water too which I like because then I know he's not getting cold.