(Y/D) tells Ratchet she's not ready to have a sparkling. He tries to wait until she's ready until he begins his heat cycle, and the only true relief is fragging. (Y/N) can't deny her sparkmate relief.
Warning; sexual content

When the two Autobots wake up the next morning, they realize what they've done. Both panicking in their processor, thinking they didn't talk about having a sparkling. All they can do now is keep this to themselves, and hope (Y/D) isn't sparked. They return to the base and claim they wanted to have a nice date under the stars and ended up slipping into recharge. Unfortunately, not everyone bought the story. Wheeljack, in particular, laughs at himself, thinking the couple is too embarrassed to say they did it.

Two weeks pass; (Y/D) isn't showing signs of being sparked, and Ratchet's scans show nothing. Ratchet wanted a sparkling, to be a sire, but he didn't want to get (Y/D) sparked if she wasn't ready.
Ratchet tries to wait until (Y/D) comes to him to tell him she's ready to have a sparkling, but today Ratchet woke up feeling his whole frame is on fire. He groaned, knowing what this meant. With (Y/D) still in recharge, Ratchet went for a drive, hoping that'll help.

He returns to find out Bulkhead, Bumblebee, and (Y/D) are heading out for a mission.
"Should only take a few hours," (Y/D) smiles, unaware of Ratchet's problem.
Great. Ratchet thinks, feeling helpless to deal with the pain of his heat cycle.
Ratchet tries to work, but that doesn't last long before he needs to retreat to his berthroom.

He sits in the berth and opens his panel. He tries to pleasure himself, but it's not working. His heat is so bad, and the thought of wanting to get (Y/D) sparked isn't helping. He wanted to wait until (Y/D) returned from the mission, but he couldn't wait. Ratchet leaves the base, not wanting the others to hear him as he keeps trying to relieve his heat cycle pain.

(Y/D) returns with the others and hoes right to her berthroom, but she doesn't find Ratchet. He's not at his usual places to work either.
"He flew out ten minutes before you guys returned," Smokescreen tells her.
That is odd. She thinks as she flies off to find him.

Ratchet returned to the cave (Y/D) brought him to three years ago. The pain got so bad, Ratchet couldn't move. There was nothing he could use as a Cybertronian sized sex toy.
So I'm stuck here for a few days? That's just great!
He lets out a roar in frustration.
"Ratchet?!" He hears (Y/D) yell, then he sees her running in, carrying her metal torch, "RATCHET!"
"I'm... fine," he assures her, "I..."
Ratchet isn't sure why now he's embarrassed to tell his sparkmate about his heat cycle. Instead, he lies on his back, showing her his interface panel. She puts a digit in his valve, resulting in Ratchet groaning. She kept going for a few minutes, but she knew the true way to relieve a mech's heat cycle.

(Y/D) sees how hard Ratchet is and peels back the flesh covering his spike. Ratchet watches as she exposes his sensitive wiring underneath the skin for his spike. Ratchet had one spot that would drive him up the walls, and she found it. She lightly touched it, earning a very loud moan from Ratchet. She smirked and stroked it while messing with his valve. Ratchet warns her he is going to cum if she continues, but (Y/D) didn't care. Ratchet couldn't help but cum when as she stroked him.
"Do you want a sparkling?" Ratchet asks.
"Yes, but not right now. I only want you."
(Y/D) meant it; she wasn't ready to have a sparkling, but the problem is the increased chance she'll become sparked while Ratchet is in his heat cycle.
Throughout his life, Ratchet never truly had his domain alpha sidekick in until today. Ratchet watched (Y/D) step back. He wasn't worried, though. He got up and saw the reader on the ground, smiling b and ready for him. Ratchet let out a terrifying roar, but (YD) wasn't afraid.

Ratchet picks her up, sits on a boulder, and puts her on his lap. He then shoved himself so deep in her he felt her metra. She screams in pleasure as Ratchet waits for her to adjust.
When (Y/D) is ready, Ratchet roughly fragged her. He sunk himself deep into her as she tightened around him with every thrust. (Y/D) screamed so much as Ratchet laughed at her pleasure. She held on to him.
As Ratchet went faster. She told him she was close, and Ratchet told her he couldn't stop. Ratchet laid (Y/D) on the ground, moving faster, pounding (Y/D) as they both were so close.

Soon, both roared, echoing in the cave. Ratchet laid on the ground feeling his instincts relax and calm him down. (Y/D) felt him wiggle in her a little, but he didn't pull out. Ratchet cuddles with (Y/D) and growls in her audio receptors. She purred and laughed; seeing him be so protective was funny. Ratchet fell asleep and held her close to his neck as she followed him soon after.

The two return the next day, again trying to hide they did it, but Ratchet is still in heat, so it's not a success this time. The couple felt both happy and awkward hearing the others talk about a possibility of a sparkling living at the base. (Y/D) still didn't feel ready, but she knows she'd have great support. Thinking about it, she becomes more eager to find out if she's sparked or not.