Mirror item that lets you build bridges, without having to edge crouch

We've all had to build bridges in Minecraft... over lava pools, ravines, or even the void, it seems every now and then, we have to get some blocks together, to help us cross a short gap. And, the strategy we've had to use is about the same. You crouch to the edge of the block, turn around to face the block you're standing on, then place a block on the face you're looking at, so you can continue your bridge. This method, while functional, is lengthy, and sometimes can be a little bit risky. So, I recommend a solution to make this process easier. My idea is the mirror-- an item you hold in your off hand, which allows you to place blocks in front of, and below you, without having to use that aforementioned, unsafe process. In other words, rather than slowly placing each block one by one, when holding the mirror in your off hand, all you have to do is look straight ahead, and a little bit down, and walk forward. Hold down the place block control, and huzzah! You're building a bridge right below your feet. Just make sure you don't run out of blocks though, or you might walk straight off, into the depths below. The mirror is a shapeless recipe, that requires an iron ingot, a crystal (revealed today) and 3 sticks. This feature I feel is something we've needed for a long time... a way to build horizontally, with an elevation, without having to hold down shift constantly. I think this feature would, similar to scaffolding, make the building process significantly easier.