I've seen that 'at a glance' is a quite widely used in many texts. However, it refers to eye or optical something whatsoever. - Sorry, I'm not a native speaker ;(. I'd like to apply it to touch sensation.
Just like "at a glance", which means "If you see something in a very short time", I'd like to use "at a touch" to express "If you touch something in a very short time, you can feel something something something."
I googled "at a touch" to find out if it reflects my idea, but it seems it is uncommon to use it. Finally I got into this site, then I clicked previous question "What does 'touch' mean in “It opened at a touch”?" to check if my idea is ok to go, but context there seems little bit different from my intention.
Does it sound so weird to native english users?