I see some people on here getting pied and messed up by friends. How do you go about finding/making friends that are willing to get you messy? Or how do you ask friends that you already have about it?

Be honest and upfront about it. It will definitely help you find out who your friends are. If they try to use it against you or use it to attempt to humiliate you, then you found out who they are and can get rid of them.

For me I start with water or food playfully than see how they react or handle it usually use water sometimes mud than
Make my way over to food like whip cream than maybe a food fight a lot of it depends on how I meet someone and how they meet me but I test out the waters and see what the vibe is like

My friends all told me I was crazy

Nope. Honesty. Also, when these people say 'friends' they are talking about people they have known forever (I would not advise asking these people), or 'friends' they met in the past year. Half my playmates (somewhere around 60-80 including some very famous models on here) were weekend visits prompted by curiosity.
Point being, find acquaintances, NOT FRIENDS.
Unless you have skills and have already put your penis in them, DO NOT RUIN YOUR FRIENDSHIPS. It is very hard to reassure a friendship when you even almost masturbate in front of them.

Make sure you know how open, and non-judgemental your friends are. If you don't have that, then don't tell people. Just take your time, and get to know them better. The only reason I got started with what I'm doing is because my friends, and I are completely open to each other. If you feel comfortable talking about your fetishes with someone, and they say it sounds like fun, maybe ask if they want to try it. If they say no, leave the conversation there. If they say yes, it's a win. Best of luck in what you do.

Other people I've met up with have all been helpers, and the last 3 I met on another site where everyone is kinky at least to a degree. It's easier to bring up things like this around them because we all talk about our interests. All have been helpers who stayed clean.

- Local from here (guy). Wonderful person, crappy schedule and communication is sporadic at best. Too bad, but it is what it is.
- Friend #1 from other site. She's a great friend but can only lift about a gallon at a time so there was an attempt. Really short, can't lift a lot, and very unsteady when not standing on the ground is a bad combo.
- Friend #2 from other site. She's a natural a this! Able to lift and pour 3+ gallons while standing on a sturdy chair, wonderful chemistry between us on video, looking forward to take #2 later this month.
- Friend #3 from other site. Hoping she can help this weekend because I have a video idea for Pi day (3/14) and it would be better with someone else doling out the punishment.

There are tentative plans to meet up with someone else from here later this year sometime so I guess that's two from umd.

OP, the best advice I can give is to keep an eye open for people who are local or regional in the meetup area. Build up some sort of background or reputation here, and vet the hell out of people first. I'm serious about this part, a neighbor when I was in school was murdered by someone he met up with online who wasn't who she said she was (long story). And one last thing, prepare to be ghosted. It happens to everyone.

Here in Brazil there was a very famous tv show called Passa ou Repassa, with a lot of pies in the face and messy challenges.

I often tell my friend: when I was a kid, my dream was to go on this TV show to be pied and messy. So my childhood dream is to get pie in the face.

Everyone loved this TV show, so usually they're like "I've always wanted to pie someone or I've always wanted be pied" and it's how I know I can tell about my fetish/desire.