people wanting to put more animalistic instincts on saiyans: mating, scenting, biting--
me: monkeys are social groomers so vegeta insists on doing bulma's makeup (which he knows the method of by heart now) and brushing her hair
people: wtf

Also consider: bathing between families is culturally acceptable in japan which is why you see goku and gohan doing it, so it follows that saiyans might have done social bathing too

What, you thought animalistic meant all sexy all the time? Nah a lot of social and mating rituals with animals can be kinda goofy

I wasn't implying that the connection between monkeys and social grooming had anything to do with that aspect of jpn culture btw I just remembered it had to be stated when totoro was brought to america bc ppl were like "why is the dad in the bath with his daughters"

And it was also shown in db canon

Anyway this leads up to goku and vegeta arguing about who primps their family better
I'm saying primp this time even though the proper term IS groom bc its getting way awkward to use it even in an animal study context

Goku: chichi has suuuuuch shiny nice hair :) thanks to how I wash it, ofc
Vegeta: sh...shut up! BULMA hasnt had to visit a stylist ONCE since we got married I'll have you know! Thanks to me!

Oh and it also follows that means saiyans enjoy getting their hair brushed/washed/etc by someone close very much but I've talked about that before and its actually semi-accepted that saiyans have sensitive hair as far as fanon goes

Goku insight nobody wanted: my hc is growing up in isolation left goku very ambivalent to put off by physical contact/affection with a lot of people, not with his grandpa ofc but with other people he had to learn and grow into it

So learning he actually REALLY likes getting his hair washed/brushed (or however much you can brush that mess) was something that probably popped up in the early stages of his marriage with chichi

Bummer thought about vegeta growing up tho: hierarchy messed with his head as did being under friezas command so, sort of parallel to goku, he became very much "dont touch me"
The remaining trio did no social grooming at all

So with bulma its like "wait this touch thing, actually, its kinda nice, this better not awaken instincts I buried though"

addendum hours later: lbr though, like my headcanon with "vegeta probably has a terrible sense of smell bc of royal breeding doing that on purpose bc they equate reliance on smell = lower class dullards" the royal family bloodline probably discouraged/attempted to breed out

the instinct/desire for social grooming

but like, it was never actually gotten rid of, or at least it wasn't in vegeta, further showing how much of an abnormality he really would have been if planet vegeta was still around