Since this is Tech forum and not GD, I am going to give a tech forum answer.
Instead of just down there grooming. I am going to give a full, body man_scaping / grooming, tips advice , opinions.
I am also going to be typing this from a single guys prospective. So depending what you partner's preferences are or there willingness to help you, there might be room for some variation in all this. Also I am in my early 30's so age & physical fitness will have barring on what I type.
1) shave between your eyebrows, and depending on how thick they are, you might want to go to a pro, and get them trimmed down or shaped.
2) save the back of your neck.
3) Take a pair of grooming scissors, and trim that arm pit hair you have down, or atleast thin it up alittle.
4) trim down your chest hair. Do not shave it off. Between 7 - 10 on your electric razor will be fine.
5) A) if you have hair around your nipple or on it, get rid of it.
6) if you have hairy knuckles shave them. Do not look like a cave man. {and for the single guys you will look more white collar, it is the little thing women notice, why do you think they get there nails done all the time.... women look at hands...}
7) back hair, yeah just go ahead and get rid of that too, or atleast trim it down. But it generally just cheaper & easier to just wax it off, and it lasts a lot longer than shaving.
8) since we are talking about appendages go ahead, shave those toes and your feet also there Frodo Baggins.
{now for that special area that started this thread}
9) shave the tree, no hair
10) shave the rocks, no hair
11) as for the area around it shave it between 3 - 8 depending on what you lady prefers. I makes it look bigger, more hygienic, and with cutting it to a short length, all the benefits of shaving it bald, but none of the itching.
12) remember to go ahead and keep trimming on out to you upper groin / thigh / lap area. Because it just looks weird if you target area is 5 or and right next to you hair around it is 10.
I did not think, it need to be said, but on second thought I will say it any way, trim you ear & nose hair. Inside and out...
Do not be scared of
nair yes it is a chick product, and has a stigma about it. But do not be scared of it. It is not that bad. And it works pretty good. Personally I have never used it
down there. But I have used it on my ears and back of the neck before to great success.
Here is a article explaining what, I was talking about above when I was mentioning the numbers when referring to hair length
https://www.menshairstylesnow.com/haircut-numbers/
Here is bread trimmer I use for most of my personal grooming needs. Experiment with what number setting / length is best for you & your partner.
https://www.walmart.com/ip/Philips-Norelco-Beard-Stubble-Trimmer-QT4014/23149308?action=product_interest&action_type=title&beacon_version=1.0.2&bucket_id=irsbucketdefault&client_guid=a1305155-a926-419b-8185-c6f39fd5c06b&config_id=106&customer_id_enc&findingMethod=p13n&guid=a1305155-a926-419b-8185-c6f39fd5c06b&item_id=23149308&parent_anchor_item_id=48745750&parent_item_id=48745750&placement_id=irs-106-t1&reporter=recommendations&source=new_site&strategy=PWVUB&visitor_id=CSOyWQWNzeWymlGjhvgRIQ