Create the tag, then the tag exists. Use other popular tags by all means, to give your post more reach, but there is no limit to tags. Then promote the use of said tag. Everything is a tag once someone writes it.
#fucketyfuck ... There I just invented a tag, now to implement it. Perhaps to balance the over supply of positive sunshine and rainbow posts. I do believe this has great potential. Too many fucking positivity posts for popular votes. Time for a revolution.
Welcome to steemit 😉