Socially Aggressive
A phrase used to describe someone who is determined to participate in or dominate a conversation or social situation. Socially aggressive people assume things are all about them and want to talk but never listen. They never feel uncomfortable because the never think about how others see them, and have no hesitation about crashing someone else's party/conversation/intimate moments.
As we were trying to cheer up Maria after her break-up, Scott wandered over and pushed himself into our circle, saying loudly that he couldn't believe the party didn't have his favorite brand of beer and then stayed for 10 minutes talking non-stop about his job. He was so socially aggressive we decided to avoid any other parties he might be at.