How can I say...?

[GTJ]

Originally Posted by SomeCallMeChris

For an all-kanji phrase that has a close meaning, I would use,
不寝番天使

'Sleepless angel(s)' or 'Unsleeping vigilant angel(s)'.

I'd recommend against it. 不寝番 means "night watch". I see why you're using the word "vigilant" as it's the adj for of "vigil", but the 番 in that word means "turn". So the statement makes no sense in this context.

天使は寝ることがいらない。

That's literally a little more like 'sleep is unnecessary for angel(s).'

If you want to make it quite clear that you mean angels as a whole and not a particular angel, maybe,

天使の皆は寝ることがいらない。

The grammar is okay, but still, this doesn't make any sense. It's not a comment on your grammar, it's a comment on the content of the sentence. If you'd go up to an English speaker and say "Angels never sleep", they look at you like you're crazy.

Maybe you can use 眠る in the same way as 寝る in these sentences, but I'm not so familiar with using 眠る.

You can't, really. 眠る means sleeping, in the middle of sleeping, or to sleep deeply. 寝る means to lay down to sleep, to start sleeping, or to sleep lightly.

So at the end of the day you would say, "じゃぁ、そろそろ寝る！”
And if someone calls you at 3am, you could say, "もぉ、眠ていた！ばか。”

Again, I have to stress that this concept makes no sense in Japanese. I've asked some of my Japanese friends and they've agreed that if they saw a foreigner with a tattoo that said something like this, they'd probably start laughing.

It's not your native language, so it has no meaning for you. Therefore don't put it permanently on your body. And no, it doesn't really look cool

[Seanus]

Wow, this guy is good. I never got proficient in the use of kanji though I did surprise some of my students after a year and a half. I used hiragana for my keitai but romaji is the easiest of course. It's like black magic to me now but some things have stuck.

[GTJ]

Originally Posted by Seanus

Wow, this guy is good. I never got proficient in the use of kanji though I did surprise some of my students after a year and a half. I used hiragana for my keitai but romaji is the easiest of course. It's like black magic to me now but some things have stuck.

Romanji is killer; if I see a huge block of text written in romanji, I can't read it, lol

Lock down hiragana and you're set. The cool thing about using a keitai or the net is you can choose kanji instead of having to remember how to write them. So if you can recognize it, use it! Just dont use kanji you haven't seen before or dont know... lord knows I've made some fantastic cockups that way, hehe. Also, in the beginning, I was like "hey sweet I can use kanji and look smart!" but the backfire is that the japanese person you're mailing says "oh cool they're really good at kanji" and.. you end up not being able to read whatever they send you. XD