many girls never even asked me for my age actually. (I'm in my 30s and have a bunch of references, preferred 411 which shows my age and a short bio, so maybe that's why). just see the girls who are OK with your age, there are plenty of them.
two call system is basically a way to get the next client ready at the location without giving full details right away. first call she gives you the address and when you get to the location, she gives you the room number.
it's mostly emails and texts these days though. provider I saw today only used email. every girl and agency have their own preference for communication.
1.get a preferred 411 first or date check. You're going to need to be verified with those 3rd party verification sites... , unless you don't mind giving your employment info to her.
2.find the girl you wanna see, make sure she's well reviewed by guys who have a bunch of reviews (this increases the chance of her being who she says she is)
3. get to the location with right donation. show up very clean & groomed.
4. don't make girl uncomfortable, don't come off sounding too desperate or bombard her with calls texts emails, don't ask her real name or real personal number, etc. (at least not until she considers you a friend in real life), don't ask for bareback sex (BBBJ is OK tho) . don't show up drunk or drugged. just be a gentleman who acts mature, regardless of age, and you'll be fine
4. enjoy
5. leave when time is up.