How do I ask him to 😛✌🏼?

So my boyfriend and I have been together for almost two years. I go down on him somewhat regularly and we have sex all the time. It was never something that happened in the first year of our relationship and then one day he did and then the next time we had sex he did and then he hasn’t done it since and I would really like that tk change. Problem is I am the most shy and non-confrontational person ever and need advice!