Its when a man has sex with a pregnant woman by placing his penis
between the underside of her breast and the top of her pregnant belly
. You have to approach her from the side and push her breast and belly together to make it tighter.
While my wife was 8-9 months pregnant, I noticed that there was a nice space between the bottom of her breasts and the top of her belly..almost like cleavage and I thought it would be hot to have sex with that part of her body just like titty fucking
. So we called it the Bump Hump.