Safe sex is a given until you're all tested clean, and condom use is smart whenever you play with someone you don't know. Here, we assume that everyone is DDF, birth control measures are in place, or everyone is comfortable without birth control. Check!
Now, onto the subject at hand. SPERM. Specifically YOUR sperm.
EVERY cuckold-Hotwife couple fantasizes about the Bull ejaculating inside the wife. NO exceptions.
Now... these fantasies may or may not translate into real life. Some wives insist on condom use. However, that doesn't mean they don't fantasize about taking a bare cock inside and getting filled with cum. They all do.
Who else fantasizes about it? The husband, that's who.
When he thinks of you fucking his wife he imagines you emptying your balls and pumping his wife full of your sperm. He wants her overflowing with your cum and he probably wants it MORE than you do.
Therefore, getting your sperm inside his wife should be your goal. If she's one of those who insists on condom use, then you should see that as a challenge and get to work on her. She really wants your cum but she needs to be persuaded. So get to work, and be smart. Work her patiently.
Use the husband as your ally. Work together as a team to persuade her, with him talking to her when they are alone, and you persuading her when you're alone with her.
Make her see it as a next step in your relationship (women are all about relationships). Also, focus on "just doing it once". If she sees it as a one-time thing she may be more willing to do it (after you do it once it's easy to get her to repeat).
Use alcohol. That one extra glass of wine may be the ticket to bareback heaven.
Push her when she's ovulating and extra horny.
Do whatever it takes, but eventually your goal should be fucking the wife bareback. No matter what they say in the beginning it's what they both really think about. So make it your mission that whenever you leave their home, or whenever you send the wife home from your place, you leave your calling card right where nature intended... between her legs!
However, let's don't forget that there are many other fun places to leave it too! I once sent a beautiful wife home to her husband with my cum sprayed on her chin, neck and tits. She rushed out to get home and show him before it dried. I thought that was hot as hell!
I once ejaculated on another wife's hair. She was a lovely latin lady with dark black locks. I shot my entire load into her hair, then used it to wipe off my cock, before sending her back to her husband.
Of course I love shooting on a stomach and nice tits, as well as all over a full, round ass.
Then there was the one time I met a married woman on our lunch break. We didn't have time to get a room for sex, but we did find a secluded nook. She was wearing a pant suit (they SUCK for sex), so I had her unzip and unbuckle her slacks. Then I fingered her and masturbated while we kissed. When I got close I pulled her panties away from her pussy then shot my entire load into her panties, spraying every bit of her pussy. After I finished I made her stick her hand into her panties and masturbate, using my cum to lube her clit.
You can get as creative as you want. But it's important to send them home with your calling card somewhere on/in them. Inside, outside, wherever.
Just give them something to point to once they get home and say "Honey, look what I brought you...".