Let's list the fluids in the human body. If we're not counting solids (which I'd hope, since we'd then include earwax and feces, which have very different, non-fluid fluid dynamics, and thus couldn't be drunk from a shot glass) then we have:
Saliva
Blood
Stomach acid
Mucus
Bile
Tear drops
Seminal fluid
Breastmilk
Pus
Urine
Amniotic fluid
Vomit
Menstrual blood
Sweat
Serous Fluid (The fluid that fills body cavities)
Synovial Fluid (which lubes up joints)
Pericardial fluid (which lubes up the heart)
Peritoneal fluid (which lubes up the pelvis)
Cerebrospinal fluid (which lubes up the brain and spinal cord)
Lymphs (which lubes up blisters and cuts)
Chyme (partly digested food)
Chyle (digests fats n stuff)
Vaginal lube (which…lubes up…yeah.)
I think that's pretty much all of them. But for simplicity I'm going to merge up the lube fluids as "lube fluid" mixed into one.
Now, to decide on the order. That depends on how much pain and discomfort each would cause and taste. The most discomforting would be the painful ones: stomach acid would start to dissolve your throat, like 125% vodka. Vomit and chyme would be next since they'd cause similar levels of pain, along with bile, which is also kind of painful. However, once in your stomach, they would be fine, just good luck talking for the next day, since you've started to fuck up your vocal chords, and also your mouth is dry as fuck.
Mucus, pus, menstrual blood and seminal fluid would be harmless but deeply unsettling to consume, since they would have a texture of lumpy custard if you drunk them any time other than first, second and first in quick succession, and you'd be likely to feel sick from that.
Then you have bone lube, breastmilk, chyle, blood, serous fluid and amniotic fluid which are tolerable drinks, if just a bit annoying, if you take your mind off them.
Then you have the basically-water crew, with tear drops, sweat and saliva, along with the lube fluids and lymph fluids.
Now to decide on the order:
To minimise pain, you're going to want to have the water-like ones in a larger glass. Drink about a shot of it, but hold it in your mouth. Tilt head back, pour two of the painful ones in and swallow quickly, and repeat this process. Now the disgusting ones. Just take these ones and know it's for the prize of being that one guy who took a shot of every single body fluid, and take your time. That way you'll be happy to taste the blood, and a refreshing drink of breastmilk. The bone lube and chyle aren't too bad to drink, and the the rest are weird but oh well. Then drink the glass of 'water' to wash out the tastes you have in your mouth and you've done it.
TL;DR: Sweat, saliva and tears.
Edit: Adding vaginal lube to the glass of water-like fluids, as it's extra drink to wash out taste.
Edit 2: NO GUYS IM NOT COUNTING HORMONES OR NEUROTRANSMITTERS
Edit 3: Yes, I know about eyeball juice. Now.