The bulk update request #5347 is pending approval.

remove implication plug_(jewelry) (115) -> gauged_ear (7928)
remove alias gauges (0) -> flesh_tunnel (2716)
remove alias ear_gauges (0) -> flesh_tunnel (2716)

Reason: Plug type piercing is not exclusive to ears.
Alias from gauges and ear_gauges to more ambiguous flesh_tunnel doesn't make sense when gauged_ear tag exists.

Step 2:

alias ear_gauges -> gauged_ear
category flesh_tunnel -> invalid
category gauge -> invalid
category gauges -> invalid

A few posts with actual fleshy tunnels are tagged with flesh_tunnel so I think it should be invalidated: flesh_tunnel -piercing.
Not sure how bad things are, but if not very bad, then mass update flesh_tunnel -> gauged_ear could be done.
Gauge and gauges should be invalidated because they could mean steampunk gauge too.