Hi, I have two female dogs. One is a jack Russell & 4 years old and has been spayed. The other is a Yorkshire terrier cross king charles spaniel, she is 15 months old & just started her second season. What I wondering is my Jack Russell has started humping my Yorkshire terrier since her season began. Is this normal & why does she do it? My husband laughs & says she is gay. Any thoughts would be appreciated. Thank you