Anon first thing sexual feelings are there from the time we are born. That's why we should not play with their gentiles , girl or boy irrespective of their gender. I'm sure you would have noticed toddlers pressing or fiddling their private parts, though they are just exploring their body parts they also get playfull. May be once or twice he played with his puppy there and it gave him the thrill hence doing it again and again. Do not panic its very common, do not make it obvious. Gently distract him, if possible hide or throw the puppy. If he tries to do distract him by taking him out, give him something to eat or bath. <br><br><br><br>

This is natural , they don't know what's masturbation ..But they do explore with their penis as they are trying to understand their body..Don't get angry . Understand that it's natural. Help him to understand and keep his toys away from it.

He is just a baby .. these actions are not be taken in an adult sense or wrong perspective ..