So I have two gliders (in tact male- gadget and in tact female- gizmo) Gadget is super sweet and loves to be held, but Gizmo BITES constantly and not in a "I'm scared "way, but in a "I want to suck your blood" way, I mean I know they are nocturnal and fly but damn lol (and she does draw blood). She absolutely HATES being held, pouched or touched for that matter and I am at an my wits end on what to do. It always seems to happen when I'm not looking or she will go out of her way to find fingers she can latch on to. And I have had no luck with the normal ways of stopping the biting (ex.blow in her face or make the "psst" sound while she is biting) I really don't know what to do and she makes me not want to get her out of the cage knowing she will be out for blood the entire time she is out of her enclosure. I have had the duo since December of 2016 btw.

I'll take a guess.
this pair was NOT gotten as babies, but are older. the female has not been handled much at all and never developed a bond with any person.
I would say you will need to keep trying to show her she can trust you, keep feeding the treats, and talking to her. you don't have to take her out of cage all the time, specially if its a bigger cage. if its smaller cage then you should take her out.
I think it will take lots of time, lots of treats, lots of patience.

My Maximus is also a vampire glider! He is 6 months old. I had him neutered a month ago, and that defiantly helped but he is still a biter! The first time I had him out he went up and down my body , biting and shaking his head side to side like a terrier! I didn't take him out for almost 3 weeks after that. instead I would sit by the cage and win him over with treats. he would lunge at me and make me drop the treat. I made headway when I used a apple box and straw. I would take a sip and hold the end of the straw and then let him drink the juice. I did this until he wasn't interested in it anymore but I would do this every day for about 3-4 days. After that I could feed him mealworms thru the bars without him lunging at me. Now he mostly grooms me but occasionally gives me a nip. He is especially fond of swinging down from the top of my hoodie and biting my nose. I haven't tried the bonding pouch since he silently chewed a hole in it during a trip to the vet. My other glider, Minnie, never bites or chews anything. They have complete opposite personalities so I've had to get creative in I how I treat them differently.
Good luck and keep us posted on your progress

It seems that, more often than not, it is the girl that has the mean streak. Cage birds are like that too, in my experience.

I would try taking the pouch out when she is sleeping and hold it shut, holding it against your body for as long as you can every day. That should eventually get her used to being close to you.