Drinking a small amount of vinegar straight should not harm you.
However do not drink a whole bottle of straight vinegar or a cup of vinegar without diluting it first.
Vinegar is acidic which makes the straight vinegar dangerous if aspirated and the straight vinegar also may cause burns to the tender tissue of the mouth and esophagus.
If you want to drink some vinegar you need to dilute it.
Or use the vinegar in recipes such as in Spinach.
I like to pour a little bit of vinegar onto my spinach so it makes it taste a bit better.
My mom has always put vinegar in with her spinach and it made me eat it better as a kid and I still love vinegar on spinach.
Just don't drink vinegar by itself though as it can cause health issues.