Curvy-laced? Crooked-laced?
What is the origin of this phrase and is there an alternative state of being?
It’s usually strait-laced, not straight-. It originally means “laced up tightly”, as in a corset or bodice.
Good example of steight laced! 
I guess that makes me straight zippered? ZIP IT!
PC
Though they are homophones in English, “straight” and strait" have different origins and meanings.
Bibliophage is right: “strait-laced” as in “straitjacket”.
“Straight” = origins Middle English “streght”, of “strechen”, to stretch;
“strait”= Middle English “streit”, from Old French and Latin “strictus” [Strict]
The OP now has me wondering about alternative states of being. I think a glass of a glass of Pinot noir would help me with this thought process.
Both Bibi and Mood are perfectly correct. So we have two strait-layced responses, but no loose-leyst actual answers to the OP, though, I guess Biliophage’s response does imply an answer. 
PC
Loosy-goosy?
Free and easy?
[sub]kinky?[/sub]
Straight-laced is the opposite of** loosely wrapped**
From Merriam-Webster’s page at ** http://m-w.com **
One entry found for straitlaced.
Main Entry: strait·laced
Variant(s): or straight·laced /'strAt-'lAst/
Function: adjective
Date: 1554
1 : excessively strict in manners, morals, or opinion
2 : wearing or having a bodice or stays tightly laced
- strait·laced·ly /-'lA-s&d-lE, -'lAst-lE/ adverb
- strait·laced·ness /-'lAs(t)-n&s, -'lA-s&d-n&s/ noun
One entry found for straiten.
Main Entry: strait·en
Pronunciation: 'strA-t&n
Function: transitive verb
Inflected Form(s): strait·ened; strait·en·ing /'strAt-ni[ng], 'strA-t&n-i[ng]/
Date: circa 1552
1 a : to make strait or narrow b : to hem in : CONFINE
2 archaic : to restrict in freedom or scope : HAMPER
3 : to subject to distress, privation, or deficiency <in straitened circumstances>
And, of course, nothing makes a straitjacket linear (or straight).
Just an aide-de-memoire.
From http://m-w.com
[sub]I hope y’all appreciate the effort I went to to make it look like the original[/sub]
Loose - laced, of course.
Slip-ons, or scuffs.
…not.