I have two German Shepherd dogs, they're five and six years old. They're not fixed and I don't have the money to do so either. They've not been exposed to other female dogs, so I guess you could say they are virgins and they way I hear, that isn't healthy for them. So, I was told that I needed to stimulate them and help them ejaculate. It's harder than I thought it would be. Is there any tips you guys could give me to so that I can help manually stimulate them? I don't want them getting sick. They could get testicular cancer.