YOLO iSUP inflation

I recently purchase a YOLO 11x30x6 inflatable board. I love being on the water with it but i have alot of issue inflating it. I have a small electric pump that i use to get most of the air into it. Then i have to use the hand pump. As soon as i get it to about 5 psi the hose gets loose. I have to hold the hose in place so it will not leak and it is very difficult to pump with one hand. I am not sure how this is supposed to lock. And every time i take the hose off air leaks before i lock the pin. Any suggestions would be helpful.