Either he has a health problem and he should see a doctor.

He only like Blow Jobs and wants to wait before he has sex.

Next time, just give him a handjob and refuse to blow him unless he gives you a solid answer to why these things happen, you can tees him but spitting or putting your mouth near is area or even just pull back the skin on the head of the genitals and just lick it like an ice cream and as you talk to him, it’ll get annoying fast so he’ll have to give you an answer.