We have Ariel who will be 4 years old on 9/2 and Harley who is now 7 months old. Other than possibly needing a step stool Harley has never had a problem trying to hump Ariel even at 3 months old when we got him. We would like to breed the two so my questions are: Is Harley too young? Ariel just started bleeding (8/28/09) so when should I remove the diaper in order for them to get together? We have never done this before and are unsure about the timing and cycle. Thanks, Kelley