Can you mask the presence of the gift?

Can you mask the presence of the gift with MASKING THE ODOR OF MAGIC?
Or any other means but gentle gift virtue?

No, but you can overcome some of the mechanical penalties with certain spells. Note, I think, even with the mechanical penalties characters should still hold the Gifted with a certain amount of disdain.

Which penalties and which spells?

Aura of Ennobled Presence (MuIm 10) and Aura of Rightful Authority (ReMe 20) are pretty useful for blunting the effects of the Gift or simply brow-beating people into compliance, but even if they manage to get the desired effect, the target may still loathe the magi directing them.

It depends on what you mean with "mask".

Keep in mind that the Gift does not produce an eerie sense of "bad stuff" that strikes people in the vicinity of the Gifted. It simply makes the Gifted feel like arrogant, untrustworthy jerks to anyone who interacts face to face with them. So if by "mask the Gift" you mean "prevent it from causing an adverse reaction", you can always do that by avoiding face to face interaction: if a magus is invisible/inaudible, or has turned into a little mouse hiding in the folds of his grog's cloak etc. the Gift will not produce effects. But if you are Gifted and interact face to face with people, those people will get that "oh, what a jerk!" feeling. You can always counter those effects with Mentem magic, like all emotions - but you are "repairing" rather than "preventing". The only known Hermetic "shield" that protects the people you interact with from your Gift is the Parma Magica. The Gentle Gift and Unaffected by the Gift (from RoP:M) Virtues can also avoid problems - note that several non-hermetic traditions can grant Virtues and so could deal with the Gift this way.

On the other hand, the Gift is also detectable through Intellego Vim spells, even when not in the immediate presence of the Gifted (the exact base for it is in some book I don't remember right now). These spells can detect even Gentle Gifts - in other words, they detect the Gift rather than the adverse effects it produces. If by "masking" you mean making your Gift undetectable by these magics, sure, some variant of "masking the odor of magic" could probably do it - but you would still produce an adverse reactions in those you interact with, barring Parma, Gentle Gift etc.

Yes, by using Invisibility and staying quiet and letting the grogs do the talking.

Or, depending on what you mean (as noted above), there is a ReMe spell to do just that for one person in the House Guernicas section of HoH:TL.

I have the impression that the expression if the gift is more varied than that, and commonly includes hostility, otherworldliness, creepiness, etc.
the reason is that almost every noble treats commoners poorly at some stage, so a well dressed wizard being a jerk should be normal behaviour. (?)

Yes, you can become more charming, polite, and socially adept (overcoming the -3 penalty through Abilities), although there may always be some latent suspicion or concern.

Various spells and virtues can overcome the penalty of the Gift as well, generally in limited fashion for limited periods.

For example, my magus has Venus' Blessing. Women are convinced that he has wicked intentions... and it makes them interested.

However, I've seen players and SGs read the penalties of the Gift as everything from "Mundanes are mildly uncomfortable with Magi" to "Mundanes want to assault or even murder Magi." It varies tremendously.

Note the phrase "face to face." If you don't want to take a -3 when conversing with somebody, use a messenger or letter.

I should hope not. Otherwise the whole deal with Gentle Gift being a Major Hermetic virtue, and the fact that you are (normally) limited to only one such virtue, becomes meaningless.
Or, if this endeavour is exceptionally difficult and therefore effectively limited to skilled specialists or very powerful magi, just less meaningfull

For many reasons the fact that magi rely on mundane spokespersons and are limited in mundane, social situations is well balanced.

I really like this answer.
Not sure I "love" it, but I certainly do like it.

That's one way but it tends to be too smart for the generation of stories based on complications.

I suggest that you overwhelm the -3 from the gift with other factors such as higher abilities and muto imaginem spells. But even then the folks you've interacted with are likely to develop sore feelings about you afterwards. One way to deal with this is perdo mentem spells to scrub these undesirable feelings from their minds. This in turn opens up the possibility of warping and really annoying them if they find out that their minds are being so directly tampered with. Viola! the story guide now has a plot to run next week.

Perhaps, but IME stupid always finds a way.

Typically, the grogs go off-script, and either the magus has to live with the complications this creates, or is unable to contain himself and has to intervene somehow (also creating complications); for example.

Grogs should go off script. They should be played as if they have nothing to lose, because they are easily replaced both mechanically and within the setting.

I think grogs should be played as if they have everything to lose: (in no particular order) life, soul, dignity, family, friends, wealth, etc.

A grog worried about such things typically is off-script, from the perspective of the magus.

Grogs should be played in whatever way fits the character concept, imho. Just because they're not important doesn't mean they can't be interesting. The necessary part is more that the SG treats them as if nothing is lost should they die.

I've found that grogs are usually the ones with the more balanced builds, but also the ones with more practical real-world experience. As such, yeah: they go off-script from the magi all the time, simply because they aren't crackpot wizards with no social skills or any sense of proportion.

aka - they're the sane ones, ordered around by their crazy demigod employers - but they can't leave their employment, because this is either all they know, or else there are strong circumstances that prevent them from working anywhere else. (criminal background, geas, etc.)

Yes. Exactly.

Okay, am I the only person who doesn't make a setting assumption of all magi being selfish, power-hungry, reclusive sociopaths who never got through the "understanding how others work" part of being a sociopath and have no sense of the enormity of their goals or the consequences of their actions? Because this board sometimes gives me the feeling that I am, and I'd just like to confirm that I'm the weird one.