Blowjobs πŸ‘…

So my bf doesn't cum from me blowing him but he still absolutely loves it when I go down on him. We already discussed the not cumming thing and it's fine for both of us because we can really keep it going for a while which is a turn on for both of us. I really want to surprise him next time and maybe try some new things. Any tips that would drive him crazy when I blow him?