On both Xbox one and ps4 you and a friend can set each other's console as your 'home' console. You can then play their digital purchases as well as your own, but with the caveats:

- you must be signed in online to play your own purchases

- other accounts on the console you own lose access to games purchased by your account

You don't need to reveal your passwordor share accounts, just sign in on the console once and set it as 'home'.

Back on the xbox 360, there was a more involved process to do the same thing. A digital purchase really granted two licenses: one tied to your account and one tied to the specific 360 that downloaded it. My sister and I took advantage of that to share season passes for various Call of Duty games.

Useful trick, although I first discovered it when visiting family, buying a game on my account and then wondering why I couldn't play it offline back on my own console.