Anne Summers is a frilly knicker & bra shop that also sells girly 'toys'. It's not really a 'sex shop' of the kind you'd find with blacked out windows down some pissy back-ally. Quite fun and light-weight and pretty harmless too. The Horny add, is a cheeky play on words, as the girl fronting the campaign is wearing Xmas themed Reindeer Horns.
Can't say as I'm offended in the slightest myself, at least it's certainly no more gross than the rest of the commercialism rampant around Xmas IMO.