I have given a lot of guys their first enema (white can, red hose, black nozzle). I reassured them:
"You don't have to like this, but it's good for you. Tell me if you can't handle it, and I will let you get on the pot."
Some liked it and wanted another. Only one felt faint after a 2 qt. soapsuds injection. He was okay after a few minutes. One married physician had never had an enema. He claimed enemas were never even mentioned in medical school. That was the province of nursing schools. Physicians were prescribing enemas for patients in a hospital because it was just standard practice to avoid soiling the operating table. Anyway he took his 2 qt. soapsuds enema and marveled at how effective it was.
In another situation a really macho type was crossing eyes during his first enema.
"Aw! Man! I'm gonna need at least two of these."
I left him alone in the bathroom after the enema. Suddenly he yelled out. I asked,
"What's the matter?"
"I lifted the toilet seat. I saw all the little brown splatters on the bottom of the seat. Now I know what my Dad was doing alone in the bathroom all those years."
After a while he got the second soapsuds enema.
A little caution here..... Anyone who has taken Psych 101 knows that the more loudly a guy proclaims his heterosexuality the more likely he has unresolved issues. It always pays to just be yourself.