3 ms·
(supposedly) In humans, the penis is designed to pull out previously ejaculated sperm, so only one's own is left inside.
by crazydiamond 17y ago
(supposedly) In humans, the penis is designed to pull out previously ejaculated sperm, so only one's own is left inside.
- deleted 17y ago[deleted]
- zackattack 17y agoIn many animals actually, this is widely believed in ethology