The title clearly says it, 
How do I go about dragging the message author into the voice channel the bot is currently in?
Say my bot is in a voice channel alone. A command is called to play sound to the author only. 
But the author isn't in a voice channel, so I can't use the move_to(*) method, hence the word drag.
I scrounged the API reference for connections, but I can't seem to find any.
Is it even possible to drag users into a voice channel?
Of course you cannot forcibly connect a client to a voice channel - this would directly violate user privacy. Your idea is akin to 'dragging people into phone calls' unexpectedly.
discord.py rewrite - dragging message author to a voice channel