Hmmm...
No expert on FTM, but I know in South-East Asia MTFs are fine to use the female bathrooms. Although I have heard some reports of some close-minded co-workers objecting to colleagues they now are TS girls using the female toilets - but only rarely and only those toilets they themselves frequent.
As far as how to ask, I'd simply go to the principle or dean and put it to them that you're a FTM transgender person and would feel more comfortable using the male washroom in lieu of the female one. If they're accepting you every other way like you say, I don't see why issues regarding the toilet should be any different. It would likely be
other students from where the objections may come. All you can do is try though...
Also, I'd come armed with some factual information and leave your coy hat at the door because they may want to know the mechnics of how you expect to use a latrine etc (assuming you would want to use the latrine per se - dunno - no FTM expert, like I said!
). And if you come across as ignorant, unprepared or shy in this respect, they might think all you're doing is wanting play the 'role' or are even up to something sordid(!), as distinct from having a legitimate need for having this request filled.
