Lyric discussion by sighofthings 

The song is obviously about phone sex, but it's also about the two people (Britney and the anonymous "Telephone Man") as well. Mainly about Britney, but... moving on.

"Phonography", as she calls it, is a personal pleasure for her. This song is solely about her want for lust and the excitement behind phone sex. That's it; she isn't in love. She might not even be friends with the guy, but one can only assume this based on her inconsideration for how he might be feeling about her not wanting him for anything more than phone sex. The lack of romantic or platonic love allows her to easily see him as no more than a sexual object. The man on the other line is there merely for her own entertainment. She's also open to him about that (there will be no talk of adding you to my plan. I'll keep you connected 'long as you understand, that's how we should keep it, Mister Telephone Man), because she doesn't want him to develop any sort of feelings for her. If he were to fall in love with her, the phone sex fantasy she's living would be destroyed.

Hope this helps

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