I have heard of breeders putting two males in with a female, thus making them feel the competition. Just keep an eye on them if they do start to fight seperate them. Another way is to take another males sperm plug and put it on the back of the female, this has induced breeding. Also another method is to dampen the shed of another male and put it in with the male and female you are trying to breed. You can also try putting a little water on the male and female, this has worked making them think a storm is arising inducing the instinct to breed. Goodluck!