The situation: We wanted to create a set in which we put a spotlight very specifically and concentrated on the face. I used my little snoot for this (I'll link it to you at the bottom of the post). It's great in itself - but the problem was that the cone of light was still too big for us.
The solution: a cardboard roll - in our case a kitchen roll. We attached this to the snoot with gaffa tape - I use the silver one here, by the way, as the black one actually sticks much better and is more likely to destroy the roll when you remove it again.
Of course, the whole thing is easier if you have a snoot available, because you already have a narrow cone of light. And thanks to the round shape, you don't have to tinker to attach a roller. But you can also mount such a roll on a system flash.
With studio flashes, however, please only do this with the light shaper attached, as otherwise everything can get too hot, especially with an active modeling light. Cardboard and heat are not great friends!
I'll show you another time how you can easily build such a snoot for your system flash yourself. But it's also cool and easy - I promise.