In the Maguire movies, the webs Spidey spun were organic. It was part of the mutation from the spider bite. However, in the original stories the webs came from invention. Peter Parker invented a solution and web-shooters that he wore on his wrists. There was a trigger in each palm that he would double tap to shoot his webbing. So, the hand motion we’re all familiar with… RIGHT? is more practical. He’s using his two middle fingers to press the trigger. GGGGEEEEEEEEKKKKK!!