how to make custom pie menu category

You can't copy EA's Funny/Romantic/Etc. categories completely as they are actually slightly different, but yes you can make a regular pie menu like the rest of the game (Actions, Magic, etc.). No there isn't a tutorial yet, but you're like the fourth+ person to ask in less than a month so it's on my to-do list now. It is incredibly simple to make though. Find an EA base piemenucategory and adjust it to how you want it to be, give it a new instance/name/tuning ID. You can either add an icon or remove it as well.

<?xml version="1.0" encoding="utf-8"?>
<I c="PieMenuCategory" i="pie_menu_category" m="interactions.pie_menu_category" n="pieMenuCategory_PetCare" s="159039">
<T n="_collapsible">False</T>
<T n="_display_name">0x56089708<!--String: "Pet Care"--></T>
<T n="_display_priority">5</T>
<T n="_icon" p="InEP04\UI\Icons\PieMenu\Category\icon_piemenu_category_pets.png">2f7d0004:00000000:a7461f907e9cb194</T>
</I>

Don't forget to do it's accompanying SimData, otherwise you will have visual errors or crashes. Don't delete anything, you only replace.
<?xml version="1.0" encoding="utf-8"?>
<SimData version="0x00000101" u="0x00000019">
<Instances>
<I name="pieMenuCategory_PetCare" schema="PieMenuCategory" type="Object">
<T name="_collapsible">0</T>
<T name="_display_name">0x56089708</T>
<T name="_display_priority">5</T>
<T name="_icon">00B2D882-00000000-A7461F907E9CB194</T>
<T name="_parent">0</T>
<T name="_special_category">0</T>
<L name="mood_overrides" />
</I>
</Instances>
<Schemas>
<Schema name="PieMenuCategory" schema_hash="0x022065C1">
<Columns>
<Column name="_collapsible" type="Boolean" flags="0x00000000" />
<Column name="_display_name" type="LocalizationKey" flags="0x00000000" />
<Column name="_display_priority" type="Int32" flags="0x00000000" />
<Column name="_icon" type="ResourceKey" flags="0x00000000" />
<Column name="_parent" type="TableSetReference" flags="0x00000000" />
<Column name="_special_category" type="Int64" flags="0x00000000" />
<Column name="mood_overrides" type="Vector" flags="0x00000000" />
</Columns>
</Schema>
</Schemas>
</SimData>

Then, inside your interaction file that you want added to the category, insert/replace your new parent category. Usually it is somewhere around here. You'll just need to read the TDESCs or study similar interactions to find out where it goes in different interactions, but they are generally all the same.
<V n="basic_reserve_object" t="disabled" />
<T n="category">159039<!--PieMenuCategory: pieMenuCategory_PetCare--></T>
<V n="content_score" t="enabled">