So from my POV being 'teased' is all about 'the thrill of the slow reveal' - which means he will get very excited with a long and slow build up to sex.
You don't have to be together - in fact it works best with some nice sexting.
This just helps you both connect with each other sexually on a deeper level.
This stuff often works well at the start of a sexual relationship but can easily taper off more long term.
Men get aroused very easily from visual stimuli. It can be something quite innocent that can really him going. Just telling him that you desire him and are thinking about sex ('naughty thoughts') can be a real turn on.
Telling him what you want to do later on that day or what you're wearing there and then also works massively.
Even stuff like "I'm wearing that lacy bra today" via text is a great message to receive during the day. Build up and anticipation really sharpens the appetite. Big time.
A series of messages of a lightly sexual nature will work well.
That will certainly get his heart racing and you may find you will both open up about your desires messaging this way. Sometime it's easier to type it then say what you want in person.
I used to sext during the work day (with my now wife) and we'd be both highly up for it by the end of the day!
When you are at home, then wearing lingerie more around the house is a huge win. Letting him see what is underneath is massive. This works when out also - just a quick flash of a stocking top, or bra strap is enough to really whet his appetite and him knowing it's for him is very hot.
Now, when it comes to JOI specifically, I think asking him to do it whilst you watch would be great. Make him wait a bit and slowly tease him by undressing slowly. Take him right to the edge. It might sound odd reading this but trust me, it can be incredibly erotic and lead to mind blowing orgasms for both of you.