I think in all of these it is just one of them providing a massage, not sure, but hopefully some will do.

Spike gives Buffy a massage in the second of the Burn It All Away series by perletwo (Therapeautic Properties). I'd warn you though that this series doesn't stop at a satisfactory pro Spuffy place (I don't know if more was originally intended). The links to the stories are on the left of the page on the link...
Burn It All Away by perletwo
Buffy gives Spike a massage in...
Awake by betty cratchit
Buffy just wants a normal weekend, but Spike has other ideas... and a really big, possibly-mystical problem. Can Buffy find a way to fix it before it drives them both crazy? And what's it going to take to get some sleep? Fluffy, resonably short fic set during the summer just before season 5; not so much Porn w/ Plot as Porn w/ Fuzziness.There is a massage in this fic but I think it might be a really brief scene...
Could Be You by Abby
You know you wanna dance. Spike knew it, the fans knew it, and this time, Buffy knew it, too. Begins in the alley scene outside the Bronze during Fool for Love and moves swiftly off-canon.A cheeky little massage in the first short of this series (Dinner and Desert)...
Dinner Interrupted series by sabershadowkat
Buffy's date with Riley is interrupted by a certain peroxide-blond. If you want massage you can't miss this one out...
Skin on Skin by nautibitz
Mid-Season 5, Buffy's got some kinks she needs worked out. Lucky for her, Spike's got the gift of healing.Again a naughty short in a series, the second 'Caressing' has massage...
The Tempting Fate series by sabershadowkat
Spuffy porn with a dash of a plotSpike give Buffy a massage in...
Cold Day In Hell by Schehrezade and RSK
Spike arranges a Christmas surprise for Buffy after her mother's death, but gets a surprise of his own. This is pure SMUT so please be warned!I think there is massage in this...
Lovers Walk Don't Run by bloodshedbaby/tanitkd
Rewrite of Lover's Walk except Buffy and Spike wind up leaving her house alone, without Angel. What will happen when Spike locks them in the basement of the Magic Box together with less than honorable intentions?