I knit with bamboo so I push on the tip when I need to scrunch up the stitches too, but I don’t do it when knitting with my smaller needles which are metal, I have some HiyaHiyas which are very sharp.
I just figure it out as I go, haven’t made myself bleed.
To scrunch up and not poke my finger, I grab the other lefthand needle tip so I am not wounding myself. It may not be the best thing, but it works.
The other thing I thought I’d do is to wear a thimble on the second finger and then use that for scrunching. I find knitting with a thimble annoying.
However, there are good reasons for touching: it is efficient: the main reason why I touch or allow the bamboo needles to touch parts of my hands or fingers is I don’t have to look at them or may hands to knit or purl. So I can knit watching TV, listening to videos on YouTube or talk on the phone, etc.
So trade of is this: I knit at a good rhythm with the bamboo. Metal is slicker and should be faster, so instead of being relaxing for me, I am focusing on not poking myself, so that can slow me down. When I knit at a constant pace, all the stitches are uniform, but avoiding the needle, does not let me knit any faster than with the bamboo. The bamboo gets slicker from use. For me sticking with bamboo is optimal.