He convinces his sister to help him cum

Under the guise of helping him come, this guy can do something he had never done with his sister. First, he says he needs to ejaculate so that the eggs don't hurt and asks him to make a straw. As she doesn't run, her sister agrees to suck her and so she tells him to fuck her so she can unload her eggs at once. The fuck is intense and ends with an internal race that leaves her sister's pussy dripping very hot milk at the risk of leaving her pregnant after releasing all the semen.