how long are you leaving the males in with the females? Tail wagging is usually a good sign she is wanting to mate, you just need to make sure you are leaving the males in for usually 3 days on and 3 days off usually trying to feed both male and female in that time off... that way they dont get worn out... and sometimes it takes a few weeks of doing this before you will notice them locking and sometimes you might not even see them locking...