"It was good talking to you, I need to make the rounds" is understood by the extroverted sensing world to be "normal" if it is a social function. Like an old-fashioned line dance, the purpose of the get together is to maximize contact with others.
If it is family or a situation where schmoozing is not the purpose, try forcing yourself to ask questions rather than make comments. Be a little careful, as INTPs can lack emotional perspective and ask the damnedest questions, ones others would consider too blunt, too personal, or you didn't connect all the dots in your head that lead to the question, making the other person think you're uttering a nonsequitor. But asking questions lets you lead the conversation where you find it to be of the most potential, thus staving off the feeling of "I've got to get out of here."
Life is not easy for us. I suggest observing someone who can flit from conversation to conversation like a bee among flowers, and emulate their techniques.
None of it will feel comfortable. Embrace the awkward.