I saw my ex-girlfriend the other day, one thing lead to another and we were having sex. The morgue didn't seem to like my presence though.
You shouldn't joke about sleeping with corpses, people may misunderstand that it is a joke and become concerned.
It was an accident, I wanted to be with her one more time.
Rather than joking about her death, you might want to talk to someone about your feelings over her loss. Getting closure with the help of someone will be the most important step after the loss of someone important in your life.