Need advice on sex positions for plus size women

Hushlilbaby • Surprised my hubs on our 1 yr anniversary 9/28 that we are expecting#1 TTC 7mons #birthcenter #naturalbirth #due6/2015
So im a size 16 but losing and my husband is half my size. I am limber to an extent so several women on bottom are great but Of course i feel "im gonna squish him" lol and he keeps wanting me to get on top. When i am it just feels clumsy and frustrating. Any tips or ideas are greatly appreciated. Pic of us attached decent of course lol