Each psn account can have one ps4 console set as their primary console, on the primary console every other user can play your games and use your ps+ subscription on that console. So set the console of the person you are sharing with as your primary, then you can use your own account on your own console. As your own console wouldn't be primary it means you'd only be able to play your games on your console when you are signed in to psn.
You will be able to use your ps+ subscription and all the digital games you own while signed in on your own console and anyone on the console set as primary will be able to use your digital games and ps+ subscription. With this method you can buy one copy of a game and both play it together online.
Basically your primary console, anyone can use your content and subs even while offline, any console not primary you will not be able to play your digital games unless your account that owns the content is signed into psn online.
