I understand your worries but it is not possible to impregnate your sister or mother with your sperms unless there is penetration into the vagina. Sperms generally cannot sustain the hot environment and die by the time semen dries up on the bedding, clothes, and towels. However they may be able to last a bit longer in hot tubs because of warm, moist environment. But it is highly unlikely that it can enter a female s body and get her pregnant. On the other hand, the sperm is able to live in the vagina for three to four days. So it is not possible for any sort of pregnancy to occur. Hope this helps.