Meet Redwood!
 
Every few decades or so, the Princesses hire a guard they like to call the Queen’s Knight - an old title for a very old position among the royal guard. The job of the Queen’s Knight is to be her faithful retainer and servant, a trusty bodyguard and boon companion, and he must be young, of good character and posture, and handsome enough to be seen at the Princesses’ side. At least, that’s what they tell the rest of Equestria.
 
In reality, a Princess doesn’t live to be thousands of years old without having strong needs. However, a Princess’s public position prevents her from maintaining normal relationships, or even having a fling, without running the risk of a serious scandal.
 
That’s where Redwood comes in. Like many before him, Redwood is handsome, charming, and obedient to a fault. But above all other qualities that were considered when filling the position: he’s hung like an absolute beast, bigger than any other guard. This ensures that the Princesses run him ragged, whether he’s ready to go or not.
 
Satisfying one Princess’s appetite is challenging for a mortal stallion, but two is a herculean task. At least weathering the storm of their insatiable lust is a pleasure that could only be described as “heavenly.”