So yesterday, after doing oxy and enjoying ourselves, my friends and I decided to do something we love to do with our drugs, nitrous. We get it and go to a spot where we can chill and nod out (on the side of Home Depot).

Everything goes fine, nitrous hits us hard, one of my friend pukes but it's no big deal. We decide to leave to go pick up some more oxy and 2 of the people we were with went another way to get some water.

Now as we are walking to meet up with a friend we see a cop and notice he's creepin at us. He stops pulls over and asks if we were the ones who were kicked out of home depot. We said we weren't kicked out but were over there not too long ago. He asks if we have any clue why he stopped us and we say no and he says well what were you boys doing with the whip cream. This comes out of nowhere and tweaks us out but we keep our cool. We tell him we were eating whip cream and after a while the cop just goes I know what you were doing you know what you were doing so let's just get this over with.

We all just agree with him, he pats down my friend (which scared me because I had more pills on me). Then he lets us go. He said he has better things to do and it's best if we just get out of here.

Now my question is: Was there even anything he could do about us doing the nitrous? We weren't high (on nitrous) when he stopped us and he really had no proof we were doing it.

TLDR: We did nitrous, cop pulls us over 10-15min later and questions us about it, could we of even gotten in trouble for it?

I know what you were doing you know what you were doing so let's just get this over with.

We all just agree with him, he pats down my friend ...

He did not know jack shit, and had no probable cause to search your friend. His assumptions are not enough.

... He said he has better things to do and it's best if we just get out of here.

Translates to "I really don't have any reason to be hassling you, so I'm going to scare you off before any of you realize this."

He asked my friend if he could search him before he patted him down and my friend agreed because he only had a cell phone on him.

He took advantage of the fact we're minors and don't know shit about the law and our rights.

Is there any tips I could get if something like this happens again.

you were huffing whip cream cans behind the home depot?

Or did you have crackers and such?

In all honesty, you did the right thing.
As your friend consented to a search the cop didn't do anything illegal that I'm aware of.
If you ever refuse, even if the cop has no reason to search you, expect them to to get shitty. Giving a cop any reason to remember your face is generally a bad thing.
Contrary to what a lot of people tell you, if you know for sure that there's nothing incriminating on you, agree to a search if the cop seems cool.

This. This has happened to me 3 times, me and my friend got pulled over every time and we let the cop search us and got no ticket or anything(it was for a license plate light).

It was whip cream cans, we can't buy the cannisters yet as we are minors.

I was worried he wanted to search all of us because I did have pills on me, but I don't think he would of found them (they were in my key pocket).

The cop was pretty reasonable though and was a lot nicer than other cops I've had to deal with in the past. The only thing that bugged me is he thought we were lying when we said we've never been in trouble before with the law.

He didn't get our names or anything so it's not like it's kept on record.

EDIT: I realize this whole thing was stupid on our part, we shouldn't of been doing drugs where people could see us.