It is, however slightly sexist..

Why is it sexist?

I guess because it's about "servicing the man" or whatever. But you're a man so you'd benefit from it.

Why would my girlfriend doing something for me be considered sexist though?

I'm pretty sure there's a day out there for muff diving, no need to burn your bra.

Yeah, it's everyday.

Still doesn't tell me why a girl doing something for me is considered sexist though.
I really want to know the answer to this.

Maybe Vegan knows the answer.

At a guess it could be considered sexist as it's based on the whole "kitchen and bedroom" joke about how women should only exist to provide their men with steaks and blowjobs but I don't see the actual day as sexist at all.

So if I bought a girl roses and took her out for dinner on valentines day does that make it sexist because I'm doing the male stereotype of being the provider?