I have an abscess on my left buttock near the midline. it started draining on its own but i do need to apply pressure to get everything out. if not, it becomes painful. is that okay? do i need antibiotics?

Unless they are tiny most abscesses need to be surgically drained, and their inner lining removed. If not, the reaccumulate and continue to drain. In the short term a warm compress and assisted drainage can reduce discomfort. Antibiotics may or may not help.

What you described suggests an infected pilonidal cyst and you should see a doctor for care. For information on this topic: https://my.clevelandclinic.org/health/diseases/15400-pilonidal-disease