Ben Tennyson was no longer 10 but was now 18 - and boy was his cock ready to rock! He'd been doing years of adventuring - fighting with his Omnitrix to throttle bad guys and protect earth from its alien foes. But now his birthday had arrived he had a new challenge to face.

You see, Ben's cousin Gwen had the same birthday as him, and he had been waiting a full decade to show her what he really thought of her. Ben's cock had ached every night for his cousin's supply breasts and fluffy ginger mound. But under the watchful eye of their grandfather Max he had been unable to play out his fantasies. He had tried several times to use his watch to secretly seduce Gwen but all had failed. Four Arms was perfect for technique but way to big to go anywhere unnoticed. Gray Matter was small enough to hide - even in Gwen's underwear - but he wasn't exactly the most attractive creature, and Gwen didn't like the idea of sex with someone who was made of 90% brain. Ghostfreak would have been ideal, having the power to turn invisible and phase through walls. But he had gone missing from Ben's watch - and no one had replaced him yet.

But grandad Max was dead now - he had been abducted by aliens and Ben had made a half hearted attempt to save him. He probably could have saved his grandfather but he had gotten in the way of Ben's deeper urges - a dangerous mistake. Gwen was upset naturally, but Ben knew that once she got on his cock she'd be over it soon.

It was twilight as Ben entered his grandfather's old camper van. Gwen was sat sobbing at the kitchen counter.

'What's up baby doll' hollered Ben.

'Oh Ben! I can't believe what has happened to granddad Max. Can't you do something?'

'I can't save it Gwen' he said solemnly 'but I could maybe do something to cheer you up?' He said, pointing at his swelling cock in his pants.

'Hm well maybe that might help', Gwen said, her mouth watering.

'Taste the candy baby!'

Gwen got on her knees and pulled down Ben's zipper. She was about to pull out his meat when she was interrupted.

'What's the problem wench!' yelled Ben.

Gwen raised her hand and pointed it, shaking. Ben's watch had begun to glow.

'Oh what now - every time I have the chance you take this away from me! There can't be another software update today!'

But no, the software was fine. What Ben didn't know was that a new alien had been added to his watch - one that would change his life.

His watch flipped through the creatures until it reaches number 9 - where Ghostfreak used to be. Instead there was an outline of some spiky creature, barely humanoid, called Mr. Johnson. Ben was overcome with curiosity, he forgot about Gwen, his cock throbbed just a little less, and he pressed the button.

The room filled with blinding light. Gwen screamed in horror. Smoke filled the campervan.

Gwen recoiled. Her body lay flat against the window of the RV for a few agonising seconds. A figure was emerging from the fog.

'Well that wasn't what I was expecting' chortled Ben, in a voice that sounded barely familiar to Gwen.

'What the hell happened?'

'I think- I think something awesome just happened!'

As the fog cleared, Gwen squinted to see Ben's new form; a smooth purple alien with large nipples, slick abs, and a throbbing Johnson the size of her arm in between his leg.

'This watch never lets me down' Ben grinned.

If Gwen's mouth was watering earlier, it was practically gushing now. She was so horny it made her dizzy, and she climbed from up the wall and crawled on all fours towards Ben, slobbering on the floor as she made her way forward.

'I guess we have no interruptions now!' said Ben.

'Gimme gimme gimme'. Gwen couldn't take it any longer.

She could only fit twenty five per cent of the schlong into her gob, but it was enough. The feeling of her lips being stretched and cheeks puffed was orgasmic enough as it is. She popped her mouth over the head a few times, testing the waters, before going to town on Ben's new purple toy.

'Take it girl' Ben smiled.

As she sucked diligently, she reached a hand up to one of the long nipples on Ben's chest, and twisted. It began do vibrate.

If Gwen's mouth wasn't open wide to begin with, it was now.

'Well I'm going to need to try that now. Quick - lie down.'

'But wait', pleaded Ben. But it was too late. If there could be a fourth Newton's law to physics and the universe, it was that nothing could stop a horny girl. Gwen pushed her cousin to the floor and sat herself on his chest, using his elongated vibrating nipples as a vibrator toy. She started moaning.

'A girl's gotta do what a girls gotta do!'

'I ain't complaining' Ben acknowledged when he saw the view of her ass on his chest, his nipple making her wetter and wetter.

'Let's see what else this bad boy can do'.

Ben stuck out his tongue, realising that it could reach a good six inches at best. It was flexible too, and soon he had used it to pull down Gwen's leggings to reveal a pantieless asshole beneath.

Now Ben's tongue had begun to slobber, and he needed somewhere to put it! Ben stuck his long blue tongue deep into Gwen's ass - making her squeal.

Before she had been moaning, but now she was screaming. In the heat of the moment she had leaned forward to stroke Ben's rod. Well, it was more of a shuffle than a stroke, with both hands barely covering its girth. Her fingers held on for dear life.

Ben was now tonguing her ass quickly, and Gwen could barely hold on to his cock she was shaking so quickly.

'Time to switch things up' she chortled.

Gwen stood up and took off her underwear. Ben had missed the fluffy bush. She winked at him and slowly slid herself onto his monster johnson.

'Blimey - how did you do that?'

'I've had lots of practice - I used to ride Four Arms when he was asleep.' she laughed.

'Well - if you can ride four arms...'

'Exactly' she said as she reached the base of Ben's giant prick.

Gwen was a skilled rider, and it was exactly what Ben had always dreamed of. As she sped up, Ben took the opportunity to lift her top and start caressing her supple nipples with his elongated toungue.

'You're the best cousin!' she moaned.

Gwen couldn't speed up any more, so Ben flipped her over and plowed into her like a plow.

'I'm gonna cum!' she screamed.

'Do it for grandpa.'

And so Gwen did, her memory of grandpa Max so powerful that the orgasm triggered a cosmic event. The ghost of Max suddenly appeared, the power of the force was so strong between them.

'Well well well - look at what you young whippersnappers are up to!' chortled Max ghostly.

'Grandpa!' cheered Gwen. 'We've missed you so much!'

'I've missed you too sweetcakes. I just wanted to let you know from heaven how proud I am of both of you.'

'I thought you'd be ashamed of us pops?' inquired Ben, 'that's why we kept trying to hide it from you.'

'I was never ashamed of you kids. Incest is a healthy phase that everyone goes through. I was only upset that you never asked me to join in.'

A tear fell from Gwen's face at the same time a tear of jizz dropped out of Ben's japseye.

'I'm sorry grandpa', they said in unison.

'It's ok,' he smiled gently, 'I forgive you.'

A quiet moment of serenity fell on the family - a harmony in the universe.

'Now be a good boy and cum on your cousins face.'

'Will do grandpa, will do.'

Ben lined up his cock with Gwen's eager face, and within seconds she was covered in ropes of his jizum, the force strong enough to blow her hair back and tilt the RV like a strong wind.

Grandpa Max was crying too now as his ghost slowly rose into the air.

'Good on ya kid' he smiled, as he rose gently up into heaven.