Burping...

My daughter is 3 and in the last week she has been burping constantly.  My husband mentioned last night do you think she learned how to make herself burp???  I had not thought about it but after today I am think she has learned the skill of burping.  It is a bit embarrassing to me as a mom for my daughter to just all of a sudden burp really loud.

Now I have the task of reminding and teaching her more about manners as this is inappropriate!  I wonder if she learned it from someone or just figured it out on her own.

I would feel terrible if she did not learn it on her own and is actually just gassy, but it seems a bit strange to burp several times in an hour.  I have asked her a few different ways if she was making herself burp or if it was just coming out.  It seems that when ever I ask a question lately her response is "because this is why."  Strange response but I don't think she knows how to answer sometimes.  So I am stuck on this one, how to punish a behavior that I'm not 100% sure she is causing herself to do or if it is just natural gas???  Atleast I can keep working on the response of "excuse me."  She has that down majority of the time!