Why is my male molley fish so sexual?

i got two more molly for my tank. i put them in the water ( with them still in the bag) for tempeture feelings) it tried to mate through the bag? ._. it already mated with a female and now hes doing it to another? is this bad? is it going to effect the eggs? ( amount) is this usael for a molly to act like this? ( plus he tried to mate with a male molly? ...