I'm totally with you, I was scared to use an enema after having terrible experiences using saline enemas while prepping for GI appts. Those burn, and give me terrible cramping. Though I have a sensitive system I've been fine using Rowasa enemas - hopefully you have the same experience.
Here's my routine (to each their own, but it works for me):
1-shake bottle
2-run under hot water (w/ cap on)
3-remove cap and squeeze air out while holding bottle upright, or slightly diagnol - it's okay if some of the meds come out
4-bend over, insert most of the thin part of the tip, and sqeeze bottle until the hand holding the bottle is in a fist
"yesterday it squirt out and onto my toilet..i washed it quickly but are you saying it will come back?" I've noticed even if I get a little in the sink and clean it right away, I'll have a brown spot there the next day that has to be cleaned again. No biggie.
Good luck! I highly recommend using the enema at night. If I don't lie down within 5-10 minutes I'll start feeling slightly uncomfortable. Typically I get into bed and lie on my left side and fall asleep. The enema has never leaked. I usually get up about 7 hours later to use the restroom, and will usually just expel air and some of the solution. Then about an hour later I'll have a BM.
Let us know how you're feeling after a week or two! In my experience, enemas have not been as stressful/painful/scary/awkward as they seem.
Lastly, I used an enema during the day once and was very uncomfortable. Better to sleep w/ it in so you can remain lying down for an extended time period.