Whenever I (I'm a woman) initiate sex with my boyfriend and it isn't clearly mutual I ask something along the lines of 'are you okay with this?' before I continue. He always thanks me very sincerely for checking with him and I was wondering how often men are asked for consent because he seems so surprised! In my opinion it should just be a standard part of sex either way. (I don't ask every time if it's absolutely obvious that he's just as into it as me, but whenever there's any doubt I think it's important to check.)