Straight is a metaphor, and means heterosexual only in a limited set of contexts.
Most of the time it doesn't mean that.
It's 20 miles straight North to the border.
I'm pretty sure she's been straight with me about that.
Stand up straight and look straight ahead.
Honestly, you're such a straight arrow; would it kill you to ignore that stuff?
Be sure to position it straight up; we don't want to have to brace it.
The metaphor theme is Moralityisa Straight Line, which is part of Lifeisa Journey.
The unspoken, but very prominent, presupposition of this metaphor theme is that homosexuality
is immoral, while heterosexuality is moral, and therefore straight.
Best Answer
Straight is a specialized adverb that can pre-modify prepositions.
It can't pre-modify adverbs:
Home is usually a preposition in English (- although there is a noun home too). In the Original Poster's example we need:
Straight always pre-modifies prepositions. It must therefore occur before home.
[Now We could say:
But here straight would be an adjective, it would be describing the subject of the verb you. It has the same structure as:
The adjective straight has several meanings, but one of them is sober or not drunk. So go home straight might be understood as: