Some of the stimulant (saline) enemas sting & are nasty if you've got hemorrhoids or a fissure. Since they can pull considerable amt of fluid into the colon by osmosis, they can also give a crampingly strong urge.
I'd try a mineral oil enema first pass. It's gentle & helps hardened stool slip out easily. Maybe a tad messier.
Go with a commercial prepared enema (like a Fleet enema from the drugstore) rather than trying to do-it-yourself at home the first time.
If you dont want to go the chemical way,you can go the natural way.You can buy at most any drugstore ,a rubber bag that looks kinda like a water bottle with a long tube attached.You fill it up with warm water,insert the end of the tube and slowly let the water flow thru.That is what i do when i am constipated.If your gentle inserting it,it shouldnt hurt.You can put vaseline on the tip.I do not recommend you do it frequently,just when you havent gone for a couple days.You dont want to become dependent on it.Take care.
I have had bouts of constipation my whole life and use enemas on a fairly regular basis usually 1 or 2 a week, I have found that regular enemas make me feel better and my normal bowel movements are more regular, when I stop my enemas my bowel movements seem to slow to about two times a week, I have bowel movements between enemas, where before when I used laxatives it would take two or three days after using them, after talking to the Dr. I decided to stop using chemicels to have a BM. So think about the best way to deal with your constipation, good luck