Erik Deckers said
1 year, 1 month ago: @robzie81 There is a way — and I’m too lazy to log into WP myself to figure it out at the moment
— that you can log into your friend’s blog, and then log out of that while still saying inside the WP.com framework.
What you can try is logging in, and then closing that tab, and going straight over to WP.com. You should be logged in, but able to access your regular WP dashboard. From there, you can create as many blogs as you want, all accessible from that dashboard.
If that doesn’t work, use a different email address and create a new profile on WP.com. If you’re using Gmail as your email provider, add “+wp” after your user name and before “@gmail.com.” Gmail does not recognize anything in that spot, so you can add +WhateverYouWant, and give yourself a “new” address. Not every site will let you do that, but many of them will. It’s a great way to hide your old email address without creating a whole new profile.
And if you’re not using Gmail, well then, there’s your reason to do it.