How do shore pit vipers reproduce?

In general, female snakes are resistant to mating.

Usually, the male will hold down the female snake with its head, while trying to align its penis with the female's cloaca. When they are aligned (which demands bif effort on the male's part) the male will penetrate the female with one or two penises (known as hemipenes). Tipically, the mating time will last for an hour.

After that, the male will stay with the female for more two or three days, where they will copulate a couple more times.

As shore pit vipers are ovoviparous, they will not lay their eggs, but hatch them inside their body.