As a single, reaching out online to the couple that plays together:

DON'T: hey you lookin im down lets fuck hmu

DO: Hello. I am 28m in the such and such area. I've read your profile and I am very interested in finding out if I might be a match for you. (Include a little more information about yourself emphasizing the things about you that are in line with what the couple may be seeking. Especially volunteer additional information if your own profile isn't fleshed out. Don't make the couple have to work so hard to pull information from you. It can kinda make you seem sketchy)

DON'T use poor grammar and a lack of punctuation. In our case, Stag is looking for younger bucks who are mature, responsible and respectful. Don't make him try to decipher your messages because you are too lazy to use punctuation. You don't have to be an english major, but at least try to be clear with your words.

DON'T ask to have solo sex with either party unless they have indicated that they allow that. For the most part, couples who play together are looking for people who are into couples.

DO ask questions about the couple's expectations and wants from you. This really shows that you are interested in pleasing them. It will also answer the questions about what you can expect to get out of it.

DON'T just ask about or talk about your wants and needs. This alludes to you not taking it seriously and possibly not willing to follow directions. See above.

DO ask and DON'T assume. Every couple is different. Ask about boundaries and limits up front. Do your best to understand their dynamic.

DO show appreciation and be respectful after playtime. Ask for feedback if you are hoping for a return visit. A couple opening up their bedroom to you is a big deal. It can go a long way if you show them that you understand and are grateful for that.

AGAIN and most importantly

DO: Always ask about the couple's dynamic and expectations because some of my suggestions may not apply to all, but I think they are some pretty good guidelines for most.

If all of this seems like too much work or trouble, you aren't a fit. At least, not for us, anyway.