Thumbs up and other gestures

I'm a female teacher who sometimes puts my thumb up to indicate 'good work' out of habit. I read somewhere that this can be offensive in Japan but unsure what the gesture means to Japanese people. Can someone please tell me what the thumbs-up means in Japan? Also there are some gestures that mean completely different things in Japan than they do in the West (eg: brushing your hand towards someone in Japan means 'come here' whereas in the West it means 'go away'). Are there any gestures that Westerners make that confuse or offend Japanese people? Cheers!

(eg: brushing your hand towards someone in Japan means 'come here' whereas in the West it means 'go away')

Fyi, these are not quite the same gesture as the direction of the brushing is important. The "come here" brushing is like sweeping the person toward you, whereas the "go away" brushing is the opposite. But of course to the untrained eye they are easy to confuse.

Thumbs up mean "Good" in JP but I don't female teachers do this gesture so often(sometimes male teachers do).
I don't think it's an offensive gesture but females don't do so much. I think it fairy acceptable if you are a foreigner. It looks a bit strange gesture for me if a Japanese female teacher do this gesture(it's still okay....).

gestures are used, when they don't want to speak the meaning directly.
if you speak nothing and only show gestures, it means you don't want to express your intention to other non-related persons.
since Japanese language is understandable without gestures, Japanese often speak without watching your face.

"Thumbs up" does not mean anything in "native Japanese" gestures :) It has been imported as a western gesture for "good!", and is widely known (and accepted). As a teacher of the English language AND the culture accompanying the language, you are free to use it. While I admit some people might take it as a bit "mannish," I don't, for one, and I see no problem at all.

I've heard that some Americans indicate "bye" by holding up the hand, palm side out, and opening and closing the fist. This can be taken as "come here." (To indicate "bye!" Japanese wave their hand side to side, again, palm out.)

Americans might gesture "come here" by holding out the arm, palm side facing up, and "beckoning" with the four fingers (toward yourself). Japanese might gesture "come here" by holding out the arm, palm side facing DOWN, and beckoning. That could be where confusion could occur.

(From a Japanese female, having lived in the US/UK for several years.)

If you put your thumb up without context, probably every modern Japanese person will think it means "good/okay."

But a thumb up does commonly mean "a male lover" usually implying a secret lover. I don't think the youth use it any more, though. By the way, a pinky up means "female lover."

I don't know where you heard about it, but it's probably one of those culture-gap jokes in which people make fun of certain expression saying, "Ooh, I hope you know what that means here!" even though it usually doesn't mean much.

To me it is the hitch hiking sign but hitch hiking is rare in Japan. Making a circle with the thumb and the index finger means the money but it can be another meaning elsewhere. Sticking up the little finger by men is the sign for a mistress.
As you know the meaning of sticking up the middle finger but I know a guy in US meant to do it often as if he was adjusting his glasses so nobody realized what he was doing.
The gesture by closing the palm (see the movement by Maneki-Neko, the welcoming cat) usually & simultaneously followed by saying "kocchi kocchi or kocchi kite", come here, come this way.
The gesture by faster(throw) opening/slower closing twice the four fingers(thumb excepted) while the palm is down and the arm extended is simultaneously followed by saying "acchi ike/itte/ikinasai, dismissed, go away. This gesture infuriates my wife when I do it even for a joke. If you practice, you will get the hang of it. lol.

One more. The raising pinky and crossing with another person's and shaking is used by both genders(young) to make a promise usually by chanting "yubikiri genman" that if you break the promise, you'll swallow 1,000 needles. Ask you students for the whole lyrics.

One last thing.
The rock paper scissors game is called "jyanken" in Japan and make the hand by chanting first "jyanken pon" & "aiko de shoi", if a draw(repeated until someone wins).