How do I initiate sex with my boyfriend?

I (18f) am with my first Bf (19M) who has had two gf’s before me and sex one time before, which I have never. We have kissed and stuff but I don’t know how to push it further. I also don’t know what to think because he allowed me to touch his dick one time over his underwear for like 2 seconds, but he shooed me away and said, “Wow I felt my stomach drop really quickly, I must like you more than I thought. I’ve had less reaction to more stimulating experiences.” I don’t really know what that means? was he about to cum? Is it performance anxiety? I don’t even know. Should I wait for him to initiate? He’s also told me he cums quickly due to “performance anxiety”, but I don’t mind…