Call the Vet
A woman, whose dog was a female and "in heat" agreed to look after her neighbor's male dog while he was on vacation.
She had a large house, and believed that she could successfully keep the two dogs apart. However, as she was drifting off to sleep, she heard some loud howling and moaning sounds and rushed downstairs to find the dogs locked together and unable to disengage, as so frequently happens when dogs mate. She was unable to separate them and perplexed as to what to do next.
Although it was late, she called the vet, who answered in a grumpy voice. Having explained the problem to him, the vet replied curtly, "Hang up the phone and place it down alongside the dogs. I will then call you back and the noise of the ringing will make the male lose his erection, and he will be able to withdraw."
"Do you think that will work?" she asked.
"I can't be sure, but it just worked on me," he replied.