Submissive is when your partner gives themselves to you completely, and is willing to let you be in total control. You lead them where you want to go and you are the dominate figure during your session.
If this is something you want to take part in, make sure you discuss the boundaries with your partner. For this to be pleasurable for both, one of the most important things to do is to come up with a safe word; so if things get a little bit too intense for your sub partner, they are able to say something to let you know. You can also come up with a word to check in that they are OK and happy with how everything is going during your activities. Communication is key, so why not discuss a few things you are interested in beforehand to check they are comfortable with it as you want them to enjoy it as much as you.
Submissive is being able to trust your partner fully so you are able to give yourself to them; knowing they will take you to your limit but not force or push anything. Submission doesn't mean that they are a slave, although this can be discussed beforehand if that is something you want to try.
The Submissive partner can get dressed up in things such as collars around their neck. These can also be worn on the wrists or ankles, and can make the Dominate partner feel more powerful and in control which enhances the experience. Other props can be used such as whips and paddles for spanking, or keep your sub under control with handcuffs. Make sure you do not stray from the role too much and keep an ear out for the safe word. This is about learning one another's limits and what you both enjoy but this will happen over time which then will make the session go a lot easier, so make sure you discuss this with your chosen escort beforehand.