Thanks for getting back on that. Okay, well again this may be more generalized being that I don't know you, your Master and your likes/dislikes and limits.
Whether in text, on the phone, or on webcam it's going to be hard because you don't have physical touch in play with each other. With the obvious said, try thinking outside of the box. I'm not sure what rules are in place between you, but if you are allowed maybe throw a little light teasing into the mix (as long as it won't get you in trouble lol) by having the camera showing only parts of you and gradually bit by bit come into full frame, be surprise him by wearing his favourite lingerie of yours, if you've discussed some things like kneeling positions and how you are to present yourself to him for when the distance comes to a close, perhaps try those out by waiting for him in that position, having your hair the way he likes it. Perhaps you can even bring food into play as we all know that certain foods can be quite sexy. Eat some juicy strawberries in front of him, tease him with a banana, eat a juicy peach and let the juice run down your chin and onto your chest.. tell him you wish he was there to lick it off etc. Be spontaneous, show him you want him just as much as he wants you.
Hope this helps?