So I've recently introduced my two boys, around thanksgiving and one of them is showing a bit of a weight gain. I've also been a little weary about his gender because I have never seem him erect or his testicles, and my other male I have seen multiple times, and his testicles are always showing (I know some males can suck them in, and others do not). So I thought I would just double check with other chin owners who have more experience than myself. Thanks!