Make sure no one is left out. It is also very important to pay a little more attention to your partner. Leave out your partner and pay much attention to the third can be very bad. It is normal to be distracted by the third. After all, all people love to try new things. It is also understandable. But you should put your relationship at the first place. Threesome dating is supposed to be something that is used to spice up your relationship, not the way to get away from it.
Keep yourself participated. It can be unavoidable that someone is going to feel somewhat ignored sometime, but do not be angry. You can find your way in. Put your hands on them and please them. If they are considerate person, they know the rules of give and take. They will return the favor. Do not just sit there watching them having fun and angry about it.
When a partner leaves the room, do not start without him/her. Stop right there and wait for his/her return. If your significant other leave to the bathroom, do not make intimate contact with the third, even kissing. This is the best way to prevent anyone feeling insecure, especially when it is your partner.
Penetration is a tricky issue. It depends on different individuals. Some swinger couples don't think it is a huge matter, while some take it very seriously. Therefore, unless you are sure that your significant other is okay with you penetrating the third, do not rush to it. If she is not okay with it, do not try to make the attempt.
Do not leave love bite on the third. It could disappoint your significant other. Also, do not let the third leave love bite on your body. Therefore, for the sake of your relationship, do not leave any love bite on anyone.
Do not be selfish. Threesome hookup is more about giving than taking. You should put other two persons before you. Think about how to please them and make them happy. If you want it to be successful, pay more attention to the others than yourself.
If you are not sure of the things you are going to do and if it is going to make your partner feel uncomfortable, ask. You can ask anytime. There is never bad time to ask permissions. Sometime you might think it can be a little buzzkill. Therefore, this is why you should discuss boundaries beforehand. Before you go into bed, have a conversation first. It will make your threesomes smoother and more pleasant.