"Grandfather!" said Susan more shocked to see here grandfather here than
the fact that she was naked. She knew she was still covered in Ian and
Barbara's cum but she hoped that he wouldn't notice. "What are you doing
here?"
"What am I doing here?"  he aked. "I may ask you the same question young
lady. And why are you naked?"
"I'm just going to take a shower," she said.
"Well hurry along then," he said. "You'll catch your death wandering
around like that."
"Yes, Grandfather," she said and disappeared down the corridor.
The Doctor continued to walk down the corridor and stopped when he heard
a loud moan. He stopped and turned around and noticed the door to
Barbara's room was ajar. He moved towards it and pushed it further open
with the tip of his cane.
Inside the room he got the shock of his life at what he saw. Both Ian
and Barbara were naked and Barbara was on all fours with Ian pounding
away at her, his hands holding her breasts and playing with her nipples
as he did so. Neither saw the Doctor as they were so engrossed in each
other. Ian pulled out of Barbara and placed the head of his cock against
Barbara's arse. Barbara looked over her shoulder and nodded her assent.
Ian pushed the tip of his cock into Barbara's tight passage and the
Doctor saw her back arch as she took his entire length in her arse. Then
then stopped and Barbara let out a little gasp as she saw the Doctor out
of her corner of her eye. Ian took this as Barbara wanting more and
began to fuck her arse in steady motions. Barbara soon forgot about the
Doctor as she was overwhelmed with the feeling of Ian's thick cock
stretching her arse walls as he pounded relentlessly in her. The Doctor
turned and moved of down the corridor as fast as he could. Ian slammed
one final time into Barbara and gasped as he filled Barbara with his
cum. They lay there for a moment still connected to each other. Then
Barbara spoke.
"I think the Doctor saw us," she said.
"So," said Ian.
"What if he doesn't like what he saw."
"We're both adults, Barbara," said Ian. "To hell with what the Doctor
thinks. What matter is that what we did is what we both wanted to do.
Anyway, perhaps he liked it."
"Ian!" shouted Barbara and hit him with the pillow.
They laughed and fell back onto the bed.

The Doctor went back to the console room and sat in the wicker chair
that stood in one corner of the room. He couldn't believe that he had
watched Ian fuck Barbara in the arse. He never even thought anything was
happening between them two. He had his suspicions but he never thought
that they would be fucking under his very nose. How long had this been
going on? Was it already happening before they had came aboard the
TARDIS, or was it a more recent thing? Had them being stuck inside the
TARDIS for nearly a year with only each other's company that had led to
them fucking like rabbits? He wasn't to sure but he suddenly felt very
annoyed not that Ian and Barbara were having sex but that they were
having sex under his own roof. What would Susan say if she knew what was
going on? He knew that Susan harboured a crush for Ian. He had known
long before he had met Ian that Susan had this adolescent crush on him.
She always used to talk about his lessons when she came home from school
and what a good teacher he was and everything. Then it hit him like a
hammer. Susan was in on this. That was why she was naked when he bumped
into her the hall. Right, thought the Doctor getting up to the console
and programming in the co-ordinates for Earth. When we land I am
chucking Ian and Barbara of this TARDIS so they can corrupt Susan no
longer. How dare they defile my granddaughter like that? He had a good
mind to storm in on them and have it out with them there and then but
the thought of Ian's face as he slid in and out of Barbara's tight arse
gave him feelings he hadn't had in a long time. A very long time. Not
since the academy...