Ooooh, Severus's clothing juuuust hanging off him makes everything far sexier! And Remus's trousers riding low on his hips, guh! I love that the fumes from the potion could be causing it all, and also give a sense, with the cauldron in the background, that Severus and Remus are making steamy magic with their sexy blowjob action. :D Very hot and well done!