Why does my guinea pig rumble strut while I pet her?

[Joscelyn]

Most of the time When I pet my guinea pig, she will shake her hips and purr while walking slowly. Usually when I'm petting her bum. She looks like shes enjoying it when I pet her. I just dont know what it means exactly. My other 2 guinea pigs dont do that. My other guinea pig will purr and sink into the ground though.

 

[weepweeps]

Hello Percy does this too. I always get the feeling he really likes it. It seems to get him a bit excited and he runs off and popcorns. It’s very funny.

 

[Rivervixen]

My ozzy does this too, then again he rumbles at everything! Mainly the hay sack and their igloos. He just loves to shake his bum I think!

 

[Wiebke]

Most of the time When I pet my guinea pig, she will shake her hips and purr while walking slowly. Usually when I'm petting her bum. She looks like shes enjoying it when I pet her. I just dont know what it means exactly. My other 2 guinea pigs dont do that. My other guinea pig will purr and sink into the ground though.

Hi

Have you double checked the gender and how old are your piggies?
Illustrated Sexing Guide

In boars, rumble-strutting is much more common and a daily occurrance; they measure peacefully up against each other, display to female or just express their contentness with the world with it (I call the latter hving a moment of 'boarliness' because it often ends with a popcorn).

In sows, rumble-strutting is generally rarer and more clearer dominance related. You can see it during introductions, when sows come into a stronger season (often around 6 months at the height of teenage) or have an ovarian cyst based hormone high as adults.
Try to assert your own dominance in a friendly manner with some piggy whispering and it may likely stop as you have cleared up the hierarchy.
Understanding Prey Animal Instincts, Guinea Pig Whispering and Cuddling Tips
Who is the Boss - Your Guinea Pig or You?

I have only ever had one sow who was rumbling all the time but it was tied in with a bit of social insecurity and being very sensitive of her ranking in the group hierarchy, especially with the older neutered boar who she was contesting her hierarchical ranking with. The dominance rumble-strutting has instantly stopped with the introduction of a more dominant new successor after Gethin's death last month because the need for it is no longer there.