About 1991 or so
I'd been on a day out to Scarborough with a load of mates and I had left my coat in someone's car. I got in quite late, and because my brother was still up, the front door was still unlocked so I just walked in without thinking.

I made some toast, had a cup of tea and went to bed. I had a deadlock on my bedroom door, one of those that opens with one of those generic long star-shaped keys. Bugger, I didn't have my keys. They were still in my coat pocket and consequently, I couldn't get in.

I then remembered that my parents had the same key on their bedside cabinet so I thought I might as well sneak in, grab the key, unlock my door, put the key back and go to bed.

I opened their bedroom door and on the off-chance one of them might be awake, I whispered 'I'm just getting the key to get into my room". However, there in the dark I saw the shape of my mum sliding off the top of my dad with a rather startled "oh christ".

You think it's embarrassing being caught shagging by your parents? It's nothing compared to walking in on your parents at it. I said a rather sheepish "sorry" and shut the door sharpish. I could hear my mum chuntering on whilst I still had the problem of gaining access to my room.

I went downstairs and fetched a posidrive screwdriver and managed to unlock the door. By now I could hear my dad chuckling. I went into my room and could still hear him chuckling. I heard my mum say "it's not funny".
"It is" I heard him say and with that he started chuckling again.

The next day we all acted as if nothing had happened which was just weird, but I didn't stick around long anyway as I had to go get my keys.
( sandettie light vessel automatic New Twitter - @bollocksreally, Wed 9 Jun 2010, 9:18, 4 replies)

Yep.
Parents don't have sex - scientific fact.

Or rather, perhaps, shouldn't have sex.
( Je suis un vagabond is an unfunny, up your own arse middle class knob, Wed 9 Jun 2010, 9:33, closed)

I forgot to add
that they were at the time in their mid-50s
( sandettie light vessel automatic New Twitter - @bollocksreally, Wed 9 Jun 2010, 9:39, closed)

In which case the rule applies
Doubly so.
( Je suis un vagabond is an unfunny, up your own arse middle class knob, Wed 9 Jun 2010, 9:49, closed)

at least it was dark
(phe, Wed 9 Jun 2010, 14:06, closed)