First, knowing your penchant for top!Snape I have to rejoice at you writing what could arguably be bottom!Snape. The sex wasn't there but the submission and the release that's associated with it was. I think I'm doing a little happy dance in my chair.
I'm a bottom!Snape person not so much because of the sex but because I really enjoy reading Severus' release of his past. What that past is is the author's choice, but honestly there's just so much to work with there. To see Severus cry after...how many years has it been? That kind of release is my favorite thing to read.
An excellent use of a kink for some emotional depth. You have a way of writing something magnificent in so few words.