Well he sounds like he's peeing because he gets overly excited, so he's happy to see you guy's!

Yes please get another rat of the SAME sex as a buddy. If you want to know about proper qurantine etc. let me know as I have a lot of good links. This rat is still very young, and should get along wonderfully with another boy. I have several boys together and most get along fine. There are the occasional spats but nothing major most of the time. With only two rats, you should have no trouble at all. I will post more later as I am getting ready to go grocery shopping.