What does this GCC behaviour mean?

[Bobo]

https://vine.co/v/e3Xz9jt61b6
https://vine.co/v/e3XWETjAF06

I've had this bab, TJ, For about a year but still havnt figured it out. He does this to me and my dad (man in the video) whenever we let him (we usually dont)

Thank you!

 

[Flboy]

Hormonal! Oops!

 

[MonicaMc]

It could be hormonal. Has TJ done this ever since you got him at 5 months old? If yes, it could just be a personality quirk. If no, then maybe hormonal or something else?

 

[Bobo]

I think he did it when he was younger, but it's become more constant now. I think he just started doing it more a couple months ago.