Forget “Sex and the City”! Really wild sex erupts on “Spin City” as Charlie Sheen and Heather Locklear finally consummate their lust in a hilarious three-episode season finale.

“Charlie Crawford (Sheen) and Caitlin Moore (Locklear) have been heading for the bedroom ever since Sheen arrived when Michael J. Fox left two years ago — and in the last three episodes of this season, they’ll get more than they bargained for,” divulged an insider, who provided The ENQUIRER with an exclusive sneak peek of the sizzling season-ending story line.

“In the first of the three episodes, Caitlin dumps her boyfriend Tom to make way for Charlie — but when they go on their first real date together, it’s a bust!

“After Caitlin and Charlie go to Caitlin’s apartment and agree to be just friends, a good-night handshake turns into a night of passion. They vow to keep their romance a secret at the mayor’s office.”

That office is stirring with the usual kooks, and a very funny story line ignites as Paul Lassiter (Richard Kind) and Carter Heywood (Michael Boatman) become terrified that their vacationing buddy Stuart Bondek is going to lose his job to a young go-getter.

“In reality, the show has been covering for the absence of Alan Ruck, who plays Stuart. Ruck had been seriously ill with a life-threatening strep infection — but he’ll finally make his return in the last episode of the season,” revealed the insider.

Charlie and Caitlin face a crisis in their new romance early in the second-to-last episode, when one of Charlie’s old flames shows up.

“Charlie and the ex to off together after Charlie — adhering to the vow not to acknowledge his romance with Caitlin — says he’s not dating anyone,” revealed the insider.

“Caitlin is left behind in a jealous stew. A hurt Caitlin decides to get back at Charlie by getting close to a handsome reporter — and Charlie does a slow burn. But Caitlin’s handsome hunk turns out to be gay — and very interested in the equally gay Carter.”

The plot lines come to a hilarious climax in the very last episode, which airs on May 7.

“For starters, Carter becomes a foster parent to an 8-month-old boy, and seeing him deal with a crying baby and feedings and no sleep is a laugh riot,” said the insider.

“The happy couple, meanwhile, are being worked to death and have no energy left to have sex.”

That is, until one night when they are forced to redo a budget forecast at the mayor’s request. Soon they find themselves doing the nasty — right in the mayor’s office! The next day, they discover to their horror that the mayor has had a $100,000 pair of sunglasses — which used to belong to Jackie Onassis — stolen from his office.

“What’s worse, the mayor, played by Barry Bostwick, says they’ll be able to see who took them — because security keeps a camera in the office 24 hours a day,” said the insider.

“The mayor tells everyone that security will have the tape ready to watch at 4 p.m. — and everyone enters the mayor’s office.”

The security tape plays to the point where Caitlin fears everyone is about to see what Stuart refers to as the couple’s “naked triple lutz.”

Jumping the gun, she leaps up and confesses both the romance — and the sex in the office.

“What she can’t hear is Charlie trying to stop her — because on the screen Charlie and Caitlin who were out of camera range, cannot be seen!” said the insider.

“In the end, it all works out. Caitlin tells Charlie that what they did was stupid and irresponsible — but also fun. She tells him she’d like to do more stupid things — to which Charlie says, ‘Well, you’re with the right guy.’

“Everyone’s been waiting for Charlie and Caitlin to do the deed — and these three episodes make it well worth the wait!”