Rihanna's keeping "Love on the Brain" and her body on a bed of flowers ... lying on a floor covered in rose petals and striking a sultry pose.

The singer-songwriter threw on a tight lingerie top -- covered in roses -- and a pair of see-through stockings... leaving her backside basically exposed.

She hits a few different poses in these pics ... lying on her side in one before getting down on all fours and arching her back in a pair of sexy snaps.

And, ya gotta watch the short clip ... the camera captures every inch of her body and the smoldering expression on her face.

The post is an advertisement for the Les Roses collection -- Savage X Fenty's newest collection ... available to purchase online and in stores now.

As you know, Rihanna's spending a majority of her time working on Fenty ... recently admitting she feels God has a plan outside of music for her -- reigniting retirement rumors.

Rihanna's no stranger to stripping down for the brand either ... coming out with a lace underwear ad for the brand in a bright yellow lace ensemble back in September.

They say a rose by any other name smells just as sweet ... but, when the rose is Rihanna, she looks pretty dang good too!