Have you ever heard about a disco nap?

Today’s English
April 18th, 2017

It’s not something, as you may guess, dancing while sleeping or sleeping while dancing.  The phrase “disco nap" simply means a short sleep just before going out in the evening. A catnap also means a short sleep but it may be at any time. See the difference:

1. I had a disco nap and got ready for the evening party.
2. I had a catnap during my travel and refreshed myself.

In modern English, if you want to say that somebody is sleeping, the word “asleep" is used more frequently than “sleeping".

1. She was sleeping while I reached home. (Less common)
2. She was asleep while I reached home. (more common)

If somebody is sleeping on sofa, bench, etc. especially during the day use the words snooze, nap or doze, not sleep.
1. The student I mentioned was dozing/snoozing on the bench during the exam.
2. She felt a little tired and started snoozing on the sofa.

You don’t hurt anyone if you say that somebody is sleeping like a dog that just means “sleeping well for a long period".  If you could not sleep at all, you can try the expression “not get/have a wink of sleep" or “not sleep a wink".  You also toss and turn all night worrying about something, if you move around the bed a lot.
1. Why don’t you attend my call? Sorry, I felt dog-tired and slept like a dog.
2. I couldn’t have a wink of sleep because of the drilling sound heard nearby.
3. I was disturbed by the new problem and didn’t sleep a wink.
4. She was tossing and turning in bed disturbed by thousand and one things.

(Do you remember that somnambulist is a person who walks in sleep, suffering from insomnia and Shakespeare has successfully made use of this concept in his drama “Macbeth” through the character Lady Mabeth?)