Possibly fucking a best friend

Okay so my best friend who's a guy we're mad cool we can say whatever to eachother or whatever and I always tell him if I'm horny or something and when we talk at night he'd tell me if he's about to go jack off or some shit like its never awkward. that's just type of person I am. So we're on the phone and we're talking about sex and he asks me if I wanted too and I'm just like ???? Uhhhh. I never really thought about it but now I'm thinking about it like is this a good idea? But it's one think like hey I'm horny like hey I'm horny too why not like you know fuck with each other and keep it casual idk. I'm like idk where this is gonna go but I don't see it being awk cause that's how I am as a person nothing ever awkward to me.