YippySkippy wrote:
Oh, I just wanted to add that I am a conservative dresser. Just in case anyone thought I might have been wearing a snakeskin print skirt and a tube top at the time.

Ouch. So sorry they made you feel this way - and it what you wear doesn't matter, nobody deserves that.d
Not understanding intent is typical of autism, and it isn't a short-term solution. It's probably better to have a child who thinks the best of everyone while he's learning social skills than it is to have one who is terrified of social situations, as it gives you the opportunity to highlight the good. (I always think about the story
Flowers for Algernon in these situations)
You can spell out "I don't think those boys are being nice, let's go" so at least he knows why
you're upset, and maybe afterwards go over what they did and how it made you feel in detail, but he may just not understand it for a while: sexual comments are particularly difficult, because they are often complimentary on their face (nice legs, nice ass) - you may have to talk about the specific looks on the kids' faces, or the fact that it's rude to mention certain body parts. It takes some time. I assume you have him in social skills classes and pragmatic speech classes?
You should also report the harassment to whatever school you think these kids might go to, and to your local police - I doubt they will be arrested, but a) nobody should have to tolerate that behavior, even if it doesn't involve physical danger and b) those kids need to learn that what they are doing is harassment.