My boyfriend and I have ual problems. Help!?

I don't know if his isn't hard enough or my "hole" isn't big enough. Everytime we try "it" just "slips" out or bends. Hand jobs usually do the trick, but we just can't seem to make it fit in. Im tired of him having the pleasure and Im not. He suggested a lubricant, but I don't have a problem there. I never had before but i do use tampons. So I don't know if its him or me. Any suggestions: products, positions, etc...