It is a very important Sunnah. This is what I have read and heard different Ulama saying about cupping:
Jibra'eel (alayhis salam) made so much impression about Hijama that Rasulullah (sallallahu alayhi wasallam) thought it was going to be made Fardh on this Ummah. It is said that a person who does cupping need not continue any other form of medicine. Rasulullah (sallallahu alayhi wasallam) used to get cupped often for headache on the back of his mubarak head. He used to pay the person who did the cupping as well.
There are 7 points in the body that are said to be Sunnah:
1) Back of the head
2) and 3) Right and left shoulders (approx 2 inches from 8th disc on spinal cord)
4) and 5) Right and left back (approx in front of the kidneys/ liver position
6) and 7) Right and left thighs (frontal)
It is said that beloved Rasulullah (sallallahu alayhi wasallam) got himself cupped on the arm when he was poisoned (maybe the basilic vein, thats my assumption - its almost where you fold your arm). Cupping there will reduce the effects of poison
It is said that beloved Rasulullah (sallallahu alayhi wasallam) got himself cupped on the neck when black magic was done on him. It is said to reduce the effects of Sihr.
Theres a point on your head where your NOT SUPPOSED to get cupped. You know the anterior fontanelle (also called the soft spot) - the junction where the two frontal and two parietal bones meet. The anterior fontanelle remains soft until about 2 years of age. A Sahabi was cupped there and he is said to have forgotten to such an extent he could not even remember Surah Fathiha! So be careful whom you cup with.
If you do cupping on 19th (islamic calendar) which falls on a tuesday, you will not get that particular disease for a year.
17th, 19th, 21st are optimal dates. Tuesdays, Wednesdays, Saturdays are avoided. A friend said theres a Hadith to the effect that you should not cup on Wed and Sat while about Tue it is said that there is a time on that day, if blood is let, it will not stop flowing.
If you are cupping tomorrow morning, then you DO NOT:
1. Bathe after Isha (i.e Isha time: 8pm next day Ishraq is 6.15am)
2. Have family relations with spouse
3. Eat anything in the morning
4. Drink anything in the morning
Of course if you faint or shiver unless you take food, you can take some biscuits and tea (minus milk). Milk is to be avoided after cupping as well as it will make the blood clot. All milk products that is. Avoided until Magrib at least.
Best time is early morning after Ishraq. I tell everyone to pray Ishraq, recite 100 Durood and Istighfar, give some sadaqa and come. If they have not done those, I make them do it before cupping. You will be amazed at what can be cured with cupping. It is the barakah of the Sunnah of Rasulullah (sallallahu alayhi wasallam).
Hygiene, well depends on the person doing it. I apply honey on the marks, it will heal instantly and stop bleeding. It does not bleed actually, only bad blood comes out (if done properly). I sometimes make them drink some honey too so that they are refreshed.
You can bathe 4-5 hours after the cupping. Make sure you do not run your nails over the cut marks.
If there are brothers/ sisters who perform cupping or want to learn, try to practice with the intention of reviving the Sunnah. Try not to charge. Of course you might need money for equipment, try to buy them yourself or tell the people coming to bring them for you.
Feel free to point out errors as I pass on only what I hear, myself I am a Jaahil. I will try to post some success stories here insha Allah. Well, barakah of the Sunnah of the blessed Prophet (sallallahu alayhi wasallam) has been such that ALL have been successful.
Note: if you are on heart medicine, tell your cupper. Medication such as aspirin can give you a river of blood.