Drug dealer's have a code over the phone, so that any police tapping the line will be unable to get sufficient evidence on you.
IE. Don't say 'crack' or 'weed' over the phone.
Dont use dollar amounts or grams. ie 'two hundred bucks' or 7 grams.
Use fake names or if possible, no names at all.
Don't say the exact meeting place.
Don't sound like your shopping. ie 'Can I get a....'