You have to get the dog like to 26 as well, then what i did was get wolf and werewolf like to 100 each and submitted to the werewolf after. You should have a new scence with both of the animals and after that go back home and choose to relief yourself
It'll unlock the option to let your pet mount you. First you need to train them, just like how you teach the dog to sit. Once the trick is mastered, new options will be unlocked in [relief yourself].