Housemate walked in on my shower fantasy- is it normal??

Firstly, understand that I've always had a sh*t fetish. Secondly, now that I'm at Uni and not living with my parents, I wanted to try it out.

I woke up one morning after my housemates had stayed at a friend's, and got some bleach, surface cleaner and sponges ready as I was planning to make a mess but, of course, NO-ONE could find out (I also left the bathroom door open so that the smell would diffuse). I stood in the shower for a while, trying to pluck up the courage to do what I had sought after for so long. It was difficult to let rip at first, as it felt wrong (part of what makes it feel so damn sexy), but believe me when I say that once I had started I could do nothing to staunch the flow of overpoweringly spicy pungent excrement dripping from my unclenched anus.
I suddenly realised that the curry I had eaten last night had not been the best of ideas, and I desperately tried to force my rectum to contract, and curb this relentless flow of torrential laxative faeces bucketing from deep within me. ‘sh*t!’ I remember thinking, noticing that the plughole was becoming blocked. I tried with my toes to unblock it but the squishy, yielding faeces bubbling up in-between my toes felt rather pleasant, and I only half-realised that I had long since been working my foreskin up and down the length of my small shaft with the tight grip of my right hand, and that whilst my left hand had originally been trying to manually stop the inexorable current of slack sloppy sh*t, it was now struggling, reaching; desperate to finger my elusive prostate.

To cut to the chase, although I had locked the front door and left the key in the lock, it seems that this does not work on modern locks. Needless to say, in my state of excitement, banging against the shower walls and moaning like a howler monkey on heat, I did not notice my housemates open the front door. All I knew was the heady ecstasy only attainable through the realisation of your deepest fantasies, and as I climaxed, smearing lumpy turd into my face and hair, two of my housemates turned the corner at the top of the stairs. I tried to stop it, but it was inexorable; I ejaculated onto my stomach while trying to mouth a silent explanation to my friends, then slipped on some poo on the floor and landed with a sickening squelch on my back. I remember making direct eye contact with both of them from my spot there on the floor, laid there with half dried sh*t encrusted into every strand of my hair, thick, viscous cum drizzled over my sweat-coated body, and of course, the entire shower covered in disgusting doo-doo.

My housemates have left in a hurry, and this is where you guys come in. How can I explain it to them in a way that will make them let me stay? How can I explain to them that this was just a bit of fun? How can I stop everyone at Uni from finding out? How do you get sh*t stains out of the gaps in between bathroom tiles? And finally, is this normal? :(