FRIGHTFUL= Terrible.

DELIGHTFUL= Wonderful.

WE’VE NO PLACE TO GO= The verb HAVE is usually contracted (‘ve) when it is the auxiliary (e.g. I’ve finished) but not usually contracted when it means possession as here. Nevertheless, the rhythm of the song needs a contraction here.

LET IT SNOW!= I don’t mind if it’s snowing, it can go on snowing forever for all I care.

MAN (AmE)= In this context this is just a colloquial exclamation with no meaning, equivalent to "boy!" or "my!" or "gee!" or "wow".

I BROUGHT ME= I brought myself; I brought with me.

CORN (AmE)= Maize (BrE). Pop-corn is a kind of maize that pops open when you heat it and turns into a shapeless soft white ball that you can eat (especially when watching a movie). So corn for popping is maize to make pop-corn.

TURNED WAY DOWN LOW= If the light is turned down, it becomes less intense. Turned down LOW emphasizes the same idea. WAY is sometimes used with the meaning of "very" (that’s way too high= that’s really really high).

KISS GOODNIGHT= If you kiss somebody goodnight, you say goodnight with a kiss.

HOLD= To hold someone is to hug them, to embrace them, to put your arms around them because you love them.

ALL THE WAY HOME= All through the way, from the beginning to the end of my journey.

THE FIRE IS SLOWLY DYING= If a fire is dying, it is extinguishing, disappearing.

WE’RE STILL GOOD-BYING= We’re still saying good-bye. Here, the word "good-bye" is used as a verb. This is not usual, but in English you can easily turn a word or a phrase into a verb. You can also turn a verb into a noun or, likewise, change grammatical categories easily.

AS LONG AS= If. / AS LONG AS YOU'D LOVE ME SO= If you accept to love me very much.
We don't use "will" or "would" in the if-clause (the sentence introduced by the conjunction IF):
- If you need me, I will help you ("will" is in the main clause, not in the if-clause)
- If she were here, I would know ("would" is not in the if-clause)
But here we're not using the auxiliary "would", but the past of the modal verb "will", and this modal verb expresses volition, similar to "want", and it may go in the if-clause:
- If you will help me, I'll try to do it (the first WILL is the modal verb, the second WILL is the auxiliary for future) = if you want/accept to help me, I'll try to do it.
- I asked her, but she wouldn't say (would = wanted, wouldn't= refused, didn't want to) = I asked her but she didn't want to tell me.
As you can see in the examples, when we use the auxiliary "will" or "would" in conversation we usually contract them, but when we use the modal "will" (or its past form "would"), we don't usually contract them. But again, it is contracted in this song because the rhythm demands it.