"Let's Went...!" ... was a signature line of "Pancho", the Cisco Kid's trusty side kick on the old TV program, The Cisco Kid...!
Typical "Pancho" quote: "Cisco...'Let's went, before we are dancing at the end of a rope, without music.
You spell that: " Phrase"... not frase.
I think it's an old hipster (bop) phrase, not unlike: "real gone". Plays with time and tense, like the reaction of two hipsters brushed back to the curb by a passing, speeding motorcycle. One saysto the other: "Man I thought he'd NEVER leave!"
Also, it's spelt phrase not frase
Some people think it's funny to use ungrammatical expressions like this. We call such people "sophomoric".
Let's went is a particularly common example of such a grammatical "joke".
CJ
Typical "Pancho" quote: "Cisco...'Let's went, before we are dancing at the end of a rope, without music.
"Lesbion our way". It's cute.