I have just finished reading Love me by Slaymuch I'm looking for fics similar to that, where Buffy asks Spike to teach her everything about how to please a man in bed. Canon or AU doesn't matter thanks

Learning Curve by Addie Logan. It's a WIP but well worth the read.
Summary: At Sunnydale High School, two things are indisputable: Buffy and Angel are the perfect couple and Buffy and Spike will always be enemies. But when one rule breaks, Buffy decides to break the other one, too, in a desperate bid to recapture Angel's heart. However, Spike soon forms a plan of his own, and Buffy begins to realize maybe nothing was ever how she thought it was.

1st story in Unexpected Universe here on TSR

carrot

This is a good one. It's complete.
Promised by Dorians Kitten
http://spikeluver.com/SpuffyRealm/viewstory.php?sid=30937

Summary: William knew that she considered him a friend or maybe even a big brother, but she'd promised to marry him once and he had every intention of holding her to it. Just as soon as he worked up the nerve to remind her, that is. Who says you can't find your soul-mate in preschool? Nominated at the Sunny D Awards and at Cradle of Humanity! Thank You.

It does have Buffy asking him to help her learn about sex.

This one fits your search perfectly! Cannon S3 during Lover's Walk.

Before I Take That Walk by pfeifferpack
http://spikeluver.com/SpuffyRealm/viewstory.php?sid=22105
Summary: Spike sobers up after Lovers Walk S3 and wonders why he wants to go back to a cheating Dru anyway. Buffy, meanwhile, tries to get a handle on a future that won't include Angel. Can two broken hearts find an island of comfort in each other's arms and then just walk away?

Thanks everyone these look great

Just a Fling by madrog. Unfort. it's a 'forever WIP'.

Forgot about Just A Fling! Here is the link:
http://nocturnal-light.net/fanfiction/story/136/Just_a_Fling

True that it's a WIP, but it does cut off in a fairly decent place. Usually I get upset with WIPs, but this one is definitely worth the read!

Does Learning Curve cut off at a decent place? I love others stories by that author and don't want a read it if there isn't a good stopping place.

I just finished reading learning curves and it cuts off leaving you hanging i praying it gets updated

I think the author left the fandom. She had some great stories.

Nnnnnooooo! I was so hoping that wasn't the case

I thought of another one. It's complete.
School of Seduction by ya-lublyu-tebya
http://www.fanfiction.net/s/3547856/1/School_of_Seduction

AU Season 5. After the whole magical engagement fiasco, Buffy realises that she needs to win Riley round again. Only problem is, there's just one person who can help her...

Ohhhh i must go read, thanks Spuffygirl

This doesn't have Buffy asking but it does have Spike teaching her about sex.

Teach Me How by dampersandspoons
http://spikeluver.com/SpuffyRealm/viewstory.php?sid=30573

Summary: Winner at the Spuffy Awards Round 14 for Best Fantasy Romance (Reader's Choice). Runner-Up at Cradle of Humanity for Best Story. Previously Nominated at Spark and Burn Round 5 for Best Angst and Best Fantasy. William Hawthorne, cir. 1878 is a womanizing aristocrat. He's content with bedding as many women as possible with no intent to marry. Elizabeth Summers is a stubborn young girl who is constantly protesting against the lifestyle that her wealthy family expects of her. When both characters' parents arrange them to be married, will William find his match or will Elizabeth scare him away, as she has all her other suitors? (Super smut eventually. Spike is a bad, rude man, after all!)