I am doing that exact area now by electrology; I am male and it is taking some time to complete, but my hair is definitely reduced. Yup, it is both embarrassing and awkward to work between my legs and cheeks, but I am very motivated, so will endure the time and cost to get it done.
For me, my bum was more difficult to begin than getting my pubic hair removed in the front. A braz “seems” more culturally acceptable (in this day) so I started there. I then have simply asked for her to keep clearing further back… and so she has. I know this differs from the straight-forward (and clear) approach recommended above. However, since you have an existing trust in place already, then you may feel comfortable with this subtler style. Just request hair removal further “up” the leg or “down” your back; your electrologist will understand and perhaps ask to confirm that you want full clearance on your backside to which you can express your wish – “oh, well sure. that would be just fine” you say
Hope you make the jump to get what you want… and then post to all of us just how great it was (and how you finally DID ask).