Which Moon Sign keeps their emotions inside?

aquarius/taurus.

MOST of them.

No one keeps their emotions inside ALL the time. But a lot of us try.
Moon in some signs will freely express their emotions .. but this is not always a good thing (Aries)

Other Moon signs are not comfortable with their emotions and try to pretend they don't exist . .this works well until the emotions build up and burst out: All Air sign positions (because they value logic and emotions are not comfortable), Taurus (because they value stability and emotions are not stable), and Virgo (because they don't feel that emotions are "useful" to follow),
Other Moon signs are too intense and will hold in their emotions (Scorpio).
And other Moon signs hide their emotions because they have self-esteem issues and are afraid of being judged by others (Capricorn)

So let's see ... The Fire Sign Moons are the ONLY signs that freely express their emotions. And maybe they shouldn't express them QUITE so much.
Also high in expressing them, are Moon in Cancer (which tries NOT to express them, but often fails) and Moon in Pisces (which tends to emote all over the place).

However, you cannot evaluate how much someone holds in their emotions without ALSO considering:
(1) The aspects that other planets make to Moon .. the aspects are MORE important on Moon-function/expression that the signs are
(2) The Ascendant, which is our superficial social mask ... an outgoing "mask" will always show more emotion than a withdrawn "mask", regardless of what sign their Moon is in.
And IF you are close to this person, you also need to consider the Descendant, which is how our mask changes when we are only around our partner.
(3) Venus .. by sign and especially by aspects to Venus. Because Venus represents our need to relate to others. What YOU see of their emotions will be colored by Venus in their chart.
(4) If you are wondering about how they handle anger, you must look at Mars (sign and aspects) .. since Mars is how we handle frustration. Questions about anger are mostly Moon + Mars.
(5) If they are shy, this will limit how freely they express their emotions. Self-esteem issues come from a badly-aspected Sun and/or Saturn strong in the chart .. Saturn in hard aspect to Sun is especially strong in causing shyness and low self-esteem. Such a person holds a lot inside and is afraid to show it to you.

It depends where the Moon Sign is placed in the chart. There are 12 houses in a chart, if in a 2nd house, the person would be emotional about their finances, values, possessions. If in the 5th house, emotional about romance, children. If in the 11th house, emotional about people, how they would feel as a humanitarian or a loner, depending on the sign. It depends on aspects to the Moon sign as well. Fire signs (Aries, Leo, Sagittarians can be loud). Air (Gemini, Libra, Aquarius) can keep their thinking a little quiet, but not necessarily inside. Earth (Taurus, Virgo, Capricorn) are practical, logical, steadfast. Water signs (Cancer, Scorpio, Pisces) feel intensely, actually Scorpio can be quiet or loud and let their emotions simmer inside, and Pisces dream for a perfect world.

Capricorn and I'd say water sign Moons try pretty hard to conceal their sensitivity until they really know you (pisces, scorpio, cancer). I mean the Moon is really about our inner world and instincts -- the side we reveal to people only after a level of intimacy or trust is reached. In this way, anyone with a Moon tries to keep their emotions inside! But I think it's the Moons with characteristically big emotions that may be more obvious about keeping them in ... ? There's just a lot to keep in. Just a theory. It's a great thing to just learn through experience, observing how different moon signs act around you. What an Aries Moon reveals and what a Pisces Moon reveals would be quite different, but probably equally personal.

Re: Been There's answer is brilliant.

Aquarius.

Libra

Nope not at all. I have Aries Sun and Pisces Moon, and I'm not attached to my emotions at ALL. I think this might partly have to do with the fact that I have Aquarius Venus, and that keeps me from really expressing myself. Pisces Moon, especially, is highly receptive to other people's thoughts and feelings, and I do get those "waves" of energy that just come over me sometimes, but it doesn't really affect my outward demeanor. I suppose the Aries Sun stifles some of the sensitivity of the Pisces Moon, and my Aquarius Venus and Sagittarius Rising completely annihilates it LOL. Sometimes I feel things and actually don't get that those emotions are a part of me. It's very weird. I would say I am very EMPATHETIC though, not emotional.

Cancer
Capricorn

Emotional responses are individual because Moon is personal. Emotions can range from Love to Fear and all those things in between . It is a type of person that may have difficulty with expression but everyone feels them ,it will always present ,one way or another, will only be repressed so long until it shows up in your actions(emotional) or health (sick) .Happy,Sad,Joy and Anger are all emotions and this can been seen by the way a person walks ,talks,frowns or handle everyday interactions.

Emotion is what makes us human and helps us to bond with other humans,but say you grew up in a hostile environment..this does not mean, if you walk around shooting people,that you don't have emotion,what it means is ..you don't have normal emotional responses for a myriad of reasons. Say you just won lotto.. you're happy as heck ?.., but you may have what we call emotional intelligence and not scream it from the roof top. or dance in the street ..you know how to stay within acceptable norms.

So individually, it is how one processes feelings(emotions) . All of the same sign ,do not evolve under identical circumstances. The Moon is instinct and it starts in the womb..All individual Moon signs. It represents your mind before you knew you had one,your survival Memories. Unlike Mercury and learning..you are inheriting this energy from your Mother during your development.. afterwards she is still your Mother. It is more profound than a label..your instincts can keep you alive and alert..like breathing ..it is natural and not just any definition from another Mother :)

a lot of them...earth, air...