Oh, great! I truly loved (and still love!) the voices you gave your Snape and Filch in this fic.
I have to admit I got disinterested enough in the sexscenes until now that I contemplated to stop reading since Snape as the 100% passive partner all the time (especially in an unequal relationship in his favour as with Filch, who even in canon is clearly deferential) didn't ring true to me and felt rather repetitive. So this was a welcome surprise!