I've seen people talk about putting two males together
It can be done but it's really not a good idea as the loser may even be more reluctant to breed afterward (especially first timer)

Use the shed of a male instead an place it in the enclosure with the animals you have paired, you can also use the sperm plug of another male and smear it on the female's back.

You can put two females in with one male.

The weather is your friends so look for low pressure.

In most cases there will not be any need for all those tricks.