this is one of my most asked questions when it comes to my NSFW content- because I play a pretty wide range of characters.
I've also heard a similar technique described as "finding a key phrase". what is a phrase or sound you associate with the kind of character or voice you want to achieve? Say that first, make that sound first, every time, until you have the voice down the way you want it!
one of my most well known 'voices' that I do [in " because it's outside of my more normal sounding voices] is the "gremlin" voice- or as I lovingly refer to it- The Renge voice. For those who don't know, Renge is a character from Ouran Highschool Host Club [best show don't @ me] and she is...so annoying. I used to use this voice to harass my dog and then it became my shitpost voice. The key phrase I used to use to get into it was "what do you think this is, some kind of harem anime?"
and it worked, every time.
anyway. Hope this helps :> if you hav any questions, feel free to ask!