I am not going to tag all this. Have fun! (Where applicable.)
 
The first commenter - no doubt in possession of highly keen observational senses and deep seated biological knowledge - to point out that they would never have enough blood in their colthoods to get it up and would all die or pass out well before accomplishing a boner, will win a free telepathically delivered thought voucher for a virtual, kerosene powered tummy raspberry machine for disclosing the one thing that breaks the suspension of disbelief about this picture of magical marshmallow talking mythological ponies.
 
Commission for King Colt. Contact me if interested!

imported from https://derpibooru.org/images/905945