Thank you for your very kind words, but if you've read so many of my posts, what I'm going to say is going to be repetitive, I'm sure.
First, I don't know how you are meeting the men you are exploring with, but there is always the option to test first. If you are performing oral on each other, than make sure they have oral swabs done.
If that's not feasible, then yes, condoms are your next safest idea, though I do understand that most people do not find those very appealing for oral sex. However, if someone wants to give or receive a blow job badly enough, they'll somehow manage, right? They do make flavored condoms, though again, those are somewhat lacking.
Oral sex is generally much less risk than vaginal or anal sex, and most experts don't think that one act of oral sex even warrants testing.
That's easy for us to say since we aren't the ones with the partner at home, but since you mentioned the partner, have you come to an agreement about what this entails? Most ethical non-monogamy includes boundaries. Is your partner comfortable with no condoms for oral?
Washing after sex does little to nothing. It's a nice gesture for your partner, of course, but as far as disease prevention, it's not worth much. It probably won't hurt if it's just a gentle soap and water, but don't use anything stronger. (We get lots of posts from people who've used industrial strength cleansers on their genitals - please don't do that.)
You can avoid the throat to maybe reduce the risk, but if you're going to do this, please note that your partner may take offense.
This is supposed to be a pleasant encounter for both you and your partner, and if you can't relax and enjoy it, don't do it. If you go into it thinking that your partner is laden with diseases, that's not good.
There is also a risk for gonorrhea and chlamydia, along with the risk for ghsv1 (if you don't have it already), syphilis and hpv.
Depending on your age, you might qualify for the HPV vaccine. I believe in Canada you can get it if you are under 27, and in some provinces, you can pay for it if you are older, or might get it for free if you are older and at risk (you probably wouldn't qualify as "at risk" based on these activities, but ask).
As you said, syphilis is rare in Canada. I answered someone the other day in Canada, and in 2022, .03% of people in Canada had syphilis. I wouldn't even worry about that.
So all in all, oral sex is low risk, but communicate with your partners.
I also meant to add that I am circumcised and I was wondering if there’s any studies that show a circumcised penis is somehow safer than uncircumcised? Also, does the duration of the activity - specifically with oral - increase or decrease the risk? For example, if oral only last for 3 or 4 minutes and is limited licking or sucking the head, is that safer than 30 minutes and full on throat contact? I apologize for the graphicness of my questions as I just want to be specific . Thanks again for allowing these questions. I’ve never seen an inquiry phrased quite this way and I’m extremely curious of what the answers might be. Amazing service you provide. Peace.