Aliasing horsecock -> equine_penis.

Reason:

Edit: I'm a failboat. Completely misread this.

However! Seeing as we have 900+ tags under "horsecock", and only 116 under "equine_penis", I'd advocate going the other way 'round. It seems fairly certain than folks prefer the "horsecock" tag, and we already have quite a few things aliased to it.

And besides, it would kill the tag on post #53617.

I like horsecock better also. I agree we should have only one tag for this prupose. also, this has already been discussed at http://www.e621.net/forum/show/10547