Umm, what is "By getting moody & bitchy like everyone else," Alex?

Obviously depends on the girl.  Some shut down the whole park, others go with the Ron White observation:  so what if the water slide's shut down, the roller coaster's still working! In other words, offer oral specials!

Some cancel out the week, some will use a sea sponge or those softcup things so that they can still have sex without the guy noticing, others will do specials because they can only do so much, etc.

which is basically a little plastic cup inserted up the vagina to catch the mentrual flow.

It seems to work pretty well.

lying to clients and even allowing them to daty during this time, and I find that disgusting. If you can't take a week off, you're not managing your money or you need another income in addition to this. My period usually only lasts 3 days, but I take 7 off.

It's really not much of a surprise for them.  My ATF schedules her vacations and time off when she knows she will be having her period.  Sure it comes a bit early sometimes and they may have to cancel an appointment or two.

I am at a point in life when nothing is regular any more so sometimes mother nature surpises me.  If I have a session scheduled during that time,  I am just honest.    I let the guy know that he will still get a stellar bj but the rest of the menu is pretty limited.  Some guys are ok with the idea and some guys ask me to reschedule.

Or, there are some forms of birth control that completely stop everything... no monthly visitor at all