English to Japanese proofreading

Hello, im making a t-shirt for a school project and wish to put a japanese sentence on it. i used google translate to translate, but when i translated it back, the sentence made no sense.
What i want translated:
"When you do something stupid..."
What google translated it to:
"あなたは愚かな何かをすると..."
What google translated it back into:
"If you are a stupid something ..."

Pls help! i dont know very much japanese (im going to take a japanese course next year though) so i have no idea what to do :/

What exactly do you want to say with that phrase? Like "when you do something stupid (you will be like this = meaning the person wearing it)"? or something like that? These humorous phrases might not translate easily, for one thing, and pronouns like "you" used as a general "you" usually don't work well, but if you can ay exactly which way you are going with it, maybe someone can help. (But that google translation back into English is no quite correct either...)

I'm doing 2 parts of text, both seperate (second part is a person talking) the first part is supposed to say "when you do something stupid" then the second says "you fool", so really that first part is just on its own.

hmm, I took a looki at ur comment again, and came up with this:
im thinking of when you do something stupid (like in anime when a guy trips and "accidentaly" slips the girls clothes off ) not when you were something stupid.. though that could be the same?..

PS: when you say the translation back to English is wrong, do you mean that the English to Japanese is correct, but the Japanese to English isn't, so I do actually have the right phrase?

I understand what you are trying to say, when you "do" something stupid :) In Japanese, too, of course there is a distinction between "doing" something stupid and "being" stupid.

What I meant when I said the translation (by google) back to English is wrong, I meant that while the Japanese, though very clumsy and not really meaningful, has the part "do" in it, the English is missing it. Sorry but google translate is not reliable.

The google translation "あなたは愚かな何かをすると..." is very clumsy in the sense that:
- The first part, "anata wa" is "you," but in Japanese we drop the general "you." And if ever, it should be "anata ga."
- The second part, "orokana nanika" is a VERY literal translation for "something stupid" or "stupid something."

If I as a Japanese speaker am to give you a translation for the phrase you want, I would say:　
どじなことをすると…
間抜けなことをすると…
バカなことをすると…
all similar phrases with different words for "stupid." But if you run this through google translate back into English, you will get the same wrong translations, so there is no way for you to verify it I suppose...

I don't quite understand the idea behind "When you do something stupid...", what is supposed to be filled in "..." , if anything can?

a phrase that the character says goes in the ... but its in another part of the picture :/

The proper translatrion of "when" depends on the ".." part, that's why I asked for that.

I agree with "..(guest)." I thought that the whole thing was just:

When you do something stupid...
(someone else says to you) "You fool."

...isn't it?

Thank you, AK.
In that case, I think your translations would be the thing.

Yes AK, thats what i mean. sry if i wasnt being clear... i dont use forums much :/

hmm, sry i didnt notice ur reply AK ( 0_0 stupidity at its best) so using any of those 3 translations should work?

Yes. I just used three different words for "stupid (thing)," with slightly different nuances.

I initially thought of the word "baka na" (the last one), meaning "dumb, foolish, stupid" but since you mentioned the example of someone tripping and accidentally doing something embarrassing, I also thought of other words.

The first one "doji na (koto)" means a "blunder," so something unintended but clumsy. The second one, "manuke na" also is close to blundering, stupid, etc.

Probably I might not undestand the nuance of whay you want say.
But these Japanese phrases might be near it.

”ふざけてばっかり　バカじゃない？”
”いつもふざける　あなたはバカ”
It is well heard in Kanto area.

In Kansai area.
”ふざけてばっかり　アホちゃう？”
”ふざけてばかり　あんたはアホ”

The word どじ sounds a bit old fashioned to me.
I would say バカやってると