Practice makes perfect. And by that, I mean to say, if you want to get larger sizes and want to try bigger pumps like sprayers, start slobut do it fairly often.

When using your handpump it's a good idea to belt off right where the diaphragm would be (just below the ribs) and go slow. Another tip would be have a nhot shower beforehand and also lay on your back when you inflate. Both will help the body stay relaxed and minimize the risk of cramping