1. Thou shalt always get consent.
Consent is key. Say it again with me. Consent. Is. Key. No matter the size of your penis, you have no rights to anybody else's body. No matter who they are, no matter the relationship you're in, you must always get clear and affirmative consent from your partner before you engage in any sexual activity. If that person is unable to give their consent, then you don't have it. If they previously provided consent, but now are saying no, then you do not have the go-ahead. If they're saying "yes" but obviously intoxicated, then you do not have consent. No means no, and yes means yes. That's it.
2. Thou shalt be generous with foreplay.
Life with a big dick means that foreplay before penetrative sex is a must. The thicker you are, the more important this becomes. For most women, being turned on simply isn't enough. Foreplay is how you ensure that she is properly warmed up and relaxed to be ready to take your large cock. The added bonus is that most women have difficulty climaxing from penetration alone, so being on top of your foreplay game and ensuring that she gets to orgasm too will make sex just that much better for both of you.
3. Thou shalt always have lube.
On top of foreplay, don't be afraid or ashamed of bringing lube into the party. While women naturally produce lubrication of their own, with a large penis that's often not enough. Having lube on hand to help reduce friction is hugely important to successful sex. Just one thing: if you're using a condom, don't use any oil-based lubes as they will weaken the latex.
4. Thou shalt listen to thy partner.
One of the worst things you can do is go through all the hassle of getting your partner ready with loads of foreplay, and then just get in and jackhammer away at her vagina like some raving lunatic. Every woman is different in what she likes in sex, and what she's willing to do with her partners. Certain positions will be more stimulating for her than others, and she'll tell you in how her body moves, the sounds she makes, and hopefully even with words what does and doesn't work for her. You should absolutely do the same. Sex is a cooperative act, so it's best if you two communicate about what are and aren't enjoying.
5. Thou shalt be patient with thy partner.
Everybody has different levels of stamina and libido, and that can vary from day to day or week to week. Add on top of that the fact that sex with a big dick can be very tiring and leave a woman sore afterwards. Patience is a key attribute in all things sex, from getting consent to engaging in enough foreplay to listening to your partner. It works best if you are understanding of their limitations and desires as they are in that moment. And you may very well have to accept that while you're ready for round two, she may be too sore to have another go.
6. Thou shalt relax and enjoy sex.
While there's certainly a lot of thought and consideration that can go into having sex with a big dick, that doesn't mean it should turn into a clinical exercise. It's sex! It's supposed to be fun! Relax and have a good time. It's romantic, it's hot, it's sweaty, it's silly, it's hard, it's awkward, and it's the most personal and intimate thing two people can do. So relax and make it a good time while you fuck the daylights out of each other.
7. Thou shalt accept thy limitations.
One of the hardest mental issues with a big dick is accepting that it comes with limitations. You'll be limited in sexual positions, you may find that traditional blow jobs are downright painful, and you could end up scaring a date away. There's that line from Spider-Man: "With great power comes great responsibility." Being well-endowed is a gift that many men desire but few have, but they don't realize that it comes with its own set of restrictions. But if you work within those boundaries, you'll be in for a good time.
8. Thou shalt bring thy own condoms.
I don't know how it became acceptable to society that women are responsible for providing condoms. That should be the man's responsibility, especially so for men with huge dicks. We shouldn't be expecting people to women to cater to our specialty needs, even more so since they cannot reliably predict what size condom we need. Women typically don't know about condom sizing and aren't likely to have the in their personal stock the exceptionally large condoms that you may require. And let's not forget the chain of custody: by bringing condoms yourself you can ensure that they are still in good condition and haven't been tampered with. Condoms are for the protection of both of you.
9. Thou shalt not flaunt thy size.
Being big doesn't mean you have a license to brag. For one, that's not something that most women are in to. Bragging about something they'll assume you're exaggerating anyway won't score you many phone numbers. But it's also just not cool in general. Having a big dick doesn't make you better in any way, you just happen to have a larger sexual organ than average. I'm not saying that you need to go out of your way to hide your endowment, just that you stand to lose far more than you gain by flaunting what your genetics gave you.
10. Thou shalt support thy brothers.
We're all in this together. Big dicks, small dicks, medium dicks, no dicks, it doesn't matter. We're all brothers and we are all kings. Stand against discrimination, stand up for each other, and stand for what's right.