Hopefully that is just the layperson description and the law itself goes into more detail what it considers consent?
Anything other than a clear, unequivocal “yes” is not consent
There, no form needed
My point was that “consent” is a vague term that might not be understood the same by everyone so for a formal, legal context like a law it would make sense to define it more precisely, including edge cases ((how) can a person consent who is unable to speak or to a person who is unable to listen,…).