how do i add a mouse keybind

i want to add a mouse keybind to make a left click detector that gives me a tag when i left click and removes the tag when i release the left click in 1.20.1 if you dont understand i mean like it gives me a tag that i can use in commands for example /give @a[tag=left_click] diamond 1. so when i left click it gives me 1 diamond but idk how to add tags like that