First Guest: Yes. Don’t you want the person you’re having sex with to be 100% into it? If you fancy sticking your penis somewhere but don’t want to ask if that’s okay, try your own hand.
Someone who was clearly put in for ‘balance’: I’m not sure that necessary. I think it would kill the mood. Consent isn’t sexy, sex is sexy.
To sum up; if you’re unwilling to ask for permission before putting your dick somewhere, you shouldn’t be putting your dick anywhere and consent isn’t sexy, it’s fucking required.