If there are no fertility issues, do not worry about it.
At the very least the pumping should stop with his ejaculation. His penis shape will remove the semen again if he keeps on pumping. After he ejaculate, just flip over for about 15 minutes while his semen liquifies inside you. You can prop your hips up on a pillow during that time to keep the semen close to your cervix.
Best of luck TTC!