Well, you changed quite a lot of you question and I can see my previous answer does not meet your needs. I'll leave it there regardless as I'll answer a completely different thing here. If you find the first answer unhelpful, tell me and I'll delete it.
First, how to chose the site for biting. You need a large amount of blood to pass through relatively surface level arteries. Neck, femoral region in the thighs, near the armpit by the axillary artery, by the elbow in the proximal region of the forearm, also the the distal portion of the forearm by the wrist. Be aware of other structures when choosing the site as a untrained bitter may cause other kinds of injuries. Think of nerves that tend to go with the arteries, ligaments and even bones if you bite too hard. If you damage any of these, the blood donor may not want to donate again or even die. Also, there's more risk of infection in the femoral site as it's near the pelvis and genital organs. It' more difficult to get hemostasis on the neck due to higher flow of blood and it's harder and more dangerous to compress if needed. Peripheral sites should be preferred to the donor, even cheaper if you want to put a price on it. Higher flow and more dangerous sites should cost more due to the risk of death and damage.
You should disinfect the site as in a surgery, using iodine and high percentage alcohol. The lips and surrounding skin of the biter should also be disinfected. That would be the antiseptic method. You can't do that to the inner mouth, thus you would need other method of prophylaxis. Just as some people with heart disease need to take a dose of antibiotics prior to any dental procedure, the biter should take this dose 1 hour before the biting is done, also, it' safer if the donor take one as well. Anesthetics are a must if you want a painless experience. Local anesthetics are just fine but might give the bite a strange taste. If the vampire want a cleaner taste skip it, if he likes to know that his victims/donors feels pain. A painful experience should cost more.
You can safely suck around 450-500 ml of blood every 3 months, giving he's health and has more than 60-70 kg.
The biter should be taught how to bite, in order not to cause any laceration or bigger trauma than its needed and try to pin point that desired artery, guaranteeing that the human will not die due to excess bleeding. There should be a medical team attending all biting session and having the authority to call it of if anything goes bad.
After the session, if the vampire transmits any disease, the donor has to take de serum or it should be checked first if his vaccine is on point. Also, some vampires might be prohibited to take the blood if they fail any medical test that show infection in high levels. The human must be fed well after the bite and need to get some rest after it for a day or more.
If the vampire is rich enough and want that nice and "flowy" blood, he can pay top price to a human who uses heparin first, as it'll be "thinning" the blood and preventing it to clot fast and the need of re-biting. Also if the human feed on high fat food prior to donating, his blood might be milkier and tastier, depending on the taste of the customer.
That's all I have again.