A Second Alicorn Heat Wave

After a few years from it, the Princesses have gone into heat again a lot soon then they though. So, they go to their personal stud, but this time. They have an extra Alicorn and that is, Twilight Sparkle. She is very hesitate to join in, but she does have feelings for him. But when a secret is revealed, can their relationship survive. Spike with all four princesses. Rated M