First off, there is no "convincing" anyone to do something they don't want to do ... that's called manipulation and leads to abuse.
However, if you're really interested in something and your partner doesn't seem as interested, there are ways to move in the direction of exploration.
1) Once you introduce a desire, allow some time for your partner to digest it Discussions about sexuality and desires should be revisited often. Tastes change; people get more curious. Revisit the discussion often - but not in a pushy way - we never want our partner to feel bullied into doing something they don't want to do.
2) Really get clear on why you want your partner to do this thing - perhaps it's something you'd like to try, but don't need. Perhaps it's intriguing to you. Perhaps it IS something you need to feel fulfilled. These are all very important to know as they start to shape your limits and boundaries on your sexuality.
3) Consider that this just may not be something your partner is willing and able to do. Can you be OK with that? If not, there's a deeper discussion that needs to happen about the relationship. Not everyone is for everyone.
If you're having trouble knowing how to share your desires with your partner or your partner wants to try something and you're hesitant & need some guidance, set up a 30-min kink talk chat with me over Voxer and let's get to it!