How do I increase flaccid size (not erect)?

I’ve been focusing on my stats and I’m a bit confused. My erect size is around 5.669” length and 4.35” girth, which I’m fine with. But when it comes to flaccid stretched length, I only get around 6–6.5 inches.

I’m not really asking about erect gains this time. I specifically want to know if there’s any way to improve flaccid hang / stretched flaccid length. Are there routines, devices, or habits that help more with flaccid size rather than erect?