I've had some success when I get drunk enough I'm less afraid of rejection in a club. I usually like to just have a dirty dance and makeout. While it's not my preferred way of approaching girls, the most success I've had has been coming up behind a girl dancing alone, brushing her arm lightly and dancing behind her. When they're responsive they're really into the dirty dancing.

Where I have problems, especially in the club is when I talk! I think I begin to interrogate and it's not a sexy flow of conversation. What are some ways to approach a girl at the bar in a club or a loud environment? How do I make talk sexy and not drag things on too long? What are key openers?

Well man first of all don't get drunk have a few drinks for a buzz but don't get drunk I made that mistake myself.

secondly as for your opener if it's near impossible to talk keep it simple. I recently remembered reading a gentleman's post on this forums ( sorry I forgot his name)

about the smile open

walk past a girl look into her eyes if she smiles say
" Is that smile all for me"
if not
" You know, you would look so cute if you learned to smile"

it was something along the lines of that but imo this is a really good opener for a loud club as it's simple.

Also watch the volume you talk to a girl with what I do is approach for the opener then adjust my body language So I'm kinda leaning back. Then I will infact lower my tone of voice so the HB has to come to me and lean in to hear ( dw she will)
so then she is moving into me then the quick hand on the shoulder kino escalation "lets dance"

ect ect you're in.