Is it normal i ejaculate a much bigger load when my girlfriend tittyfucks me?

When I masturbate on my own I have a decent sized load of cum, but when my girlfriend tittyfuck a me it is just a massive load of cum. I mean it goes everywhere, down her cleavage line, on her nipples, neck, face. Her boobs are double d's so they are pretty damn big. But is this normal to ejaculate more when she tittyfucks me versus when I masturbate by myself??