However I think you've mistaken me for an ignorant teen who can't even remember how many sex partners they've had. I won't need dental dams, lube, or condoms because I keep my standards to that.
Being able to remember how many sex partners you've had doesn't magically protect you from STDs/STIs - nor does only having one sex partner. There are plenty of people who've contracted an STD from their first ever sexual partner.
It's very very unlikely that manual sex would transmit HIV (unless you had open cuts or sores on your hands). However, as you will see from A Quickie STD/STI Risk Assessment, unprotected manual sex can transmit a number of other STDs, many of which are much more widespread than HIV is, and two of which (herpes and HPV) are incurable.
This is one of the reasons why we recommend using latex gloves and water-based lube for manual sex. Plus it makes clean-up easier, it prevents nicks or abrasions from nails or rough skin, and it makes everything much smoother .
know that's not a guarantee but what can you do but take his word?
Well, you can practice safer sex, for a start .
Sorry this was so long but I felt that parts of your post was a bit offensive and going into activities I haven't even participated in.
Please bear in mind that we're not mind-readers. We don't know what your choices are, and what sexual activities you are or aren't involved in. But whatever sexual activities you choose, you need to make sure they're safe.