Barbara Ellen said that “consent should happen before sex, not during or after” (“How to Have Sex broke my heart: it shows that consent is still a hazy concept”, Comment). Yes, consent absolutely should be ascertained between all participating parties before engaging in sex, but consent does not end there.
Consent is an ongoing process, it is not a box to be ticked, or, as Ellen puts it, “banked” as a get-out clause that enables anyone to do anything that they subsequently wish, because “hey, you said ‘yes’, remember?”