Hi, Seems he was trying to french kiss you. Have you ever french kissed before?
From what I know French kissing years ago was not as popular as now days. Many couples french kiss now days and this involves involvement with the tounge. This is why he put his tounge in your mouth. Here is a site that explains how to french kiss step by steps. It really is an art. http://m.wikihow.com/French-Kiss
I hope this was helpful. Please let me know if you have any problem getting to the site or if I can be of further help. I wish you all the best.