create implication buttjob -> grinding

Link to implication

Non-penetrative sex.

-1. This tag would be more useful leaving it at pussy-on-penis contact. Yes, I read the wiki.

Agreed with Moose. Frottage, crotch rub, and tribadism are treated as distinct from grinding, so it makes sense to treat buttjob as distinct too.

Any objections to updating the grinding wiki to say it's pussy-on-penis only?

May as well change it since that's how the tag's used anyway.

Done. Updated the wikis to clarify that all frottage tags are distinct from one another:

• grinding: pussy-to-penis.
• buttjob: ass-to-penis.
• crotch rub: pussy-to-object.
• thigh sex: penis-between-thighs.
• thigh straddling: pussy-on-thigh.
• tribadism: pussy-to-pussy.
• armpit sex: penis-in-armpit,
• kneepit sex: penis-in-kneepit.
• paizuri: penis-between-breasts.

frottage is supposed to be used for everything but the above according to the wiki, but in practice it's a mess. So I suggest making frottage the umbrella tag, if one is wanted.