flog a dead horse

UK usage

1) To try to carry on when there really is no hope of continuation. To not know when to give up.

2) A unique sexual practise that combines Necrophillia, beastiality and sadomasacism into one fun activity.

Leeds struggled to avoid relegation but they were flogging a dead horse.

by black flag June 07, 2004

Flogging a Dead Horse

For a male to persist in virginal intercourse after losing his erection

After only lasting 1 minute Sam was flogging a dead horse to Jenny

by Ginger Christ September 03, 2009