Copied this from playstations website - it has all the answers you need.
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While you are a PlayStation®Plus subscriber, other people using your PlayStation 3 system or PlayStation 4 system can access selected PlayStation Plus membership benefits from your system. You can also access your PlayStation Plus membership benefits on other people’s PlayStation 3 system or PlayStation 4 systems. The conditions for access depend on the type of console you are using.
PlayStation 4
You can activate one PS4™ on your Sony Entertainment Network account (this is known as your Primary PS4) and temporarily activate a second PS4 on your account.
PlayStation Plus benefits available to other non-subscribing users on your Primary PS4:
- Online multiplayer (subject to any parental control settings on sub accounts)
- Play downloaded games purchased with PlayStation Plus discount
- Play downloaded IGC games
PlayStation Plus benefits not available to other users on your Primary PS4:
- Purchasing PlayStation Plus discounted products from PlayStation Store
- Online game save storage
- Auto patch download
- PlayStation Plus exclusive early access to game trials
PlayStation Plus benefits available to you on a non-subscribing friend’s PS4:
- All of your PlayStation Plus membership benefits are available to you when you use a friend’s PS4.
PlayStation Plus benefits available to your non-subscribing friend when you use their PS4:
- Play downloaded games purchased with PlayStation Plus discount
- Play downloaded IGC games
PlayStation Plus benefits not available to your non-subscribing friend when you use their PS4:
- Online multiplayer (subject to any parental control settings on sub accounts)
- Purchasing PlayStation Plus discounted products from PlayStation Store
- Online game save storage
- Auto patch download
- PlayStation Plus exclusive early access to game trials
When you sign into your Sony Entertainment Network on a friend’s PS4 the system is temporarily activated on your account. Please ensure that you correctly sign out of PSN on your friend’s system to keep your account secure.
If your “PSN” account is inactive on your friend’s PS4, the system will be deactivated automatically from your account and your friend will lose access to any of your downloaded content. This content can be deleted from their system hard drive by going to 
(Settings) > System Storage Management > Applications. Next, highlight the game to delete and press Options > 
(X button).
PlayStation 3
You can activate up to two PS3™ systems for game content on your Sony Entertainment Network account.
PlayStation Plus benefits available to other non-subscribing users on a PS3 activated on your Sony Entertainment Network account:
- Play downloaded games purchased with PlayStation Plus discount
- Play downloaded IGC games
PlayStation Plus benefits not available to other non-subscribing users on a PS3 activated on your Sony Entertainment Network account:
- PlayStation Plus discounted purchases from PlayStation Store
- Auto patch download
- PlayStation Plus exclusive early access to game trials
PlayStation Plus benefits available to you on a non-subscribing friend’s PS3:
- All your PlayStation Plus membership benefits are available to you when you use a friend’s PS3.
PlayStation Plus benefits available to your non-subscribing friend when you use their PS3 activated on your Sony Entertainment Network account:
- Play downloaded games purchased with PlayStation Plus discount
- Play downloaded IGC games
PlayStation Plus benefits not available to your non-subscribing friend when you use their PS3 activated on your Sony Entertainment Network account:
- PlayStation Plus discounted purchases from PlayStation Store
- Auto patch download
- PlayStation Plus exclusive early access to game trials