If you don’t want to be ‘somewhere’, just go home. It makes me feel useful. If I have to attend a social gathering I usually sit in a chair in the corner of the room and talk to just one person at a time.
Doing this results in longer conversations with fewer people, which drains me much less than attempting small talk with many people.
This really helps.
Or, I hang out with an extrovert and let him do the talking. I have a collection of extroverts I can call upon.
Or, I find a dog to play with.
I procrastinate in the bathroom for a while or step outside to catch my breath. This helps a lot and is the reason why I love balconies. Sometimes out in a balcony I meet another introvert and hold a conversation that feels real.
We look through the maze of activity and together witness the party unfold.
Or, I ask if I can help: I pick up dishes or arrange things in the kitchen so I don’t have to make conversation.