Taste The Blood Of Dracula(1970)
Three elderly distinguished gentlemen are searching for some excitement in their boring borgoueis lives and gets in contact with one of count Dracula's servants. In a nightly ceremony they restore the count back to life. The three men killed Dracula's servant and as a revenge, the count makes sure that the gentlemen are killed one by one by their own sons.
This is the theatrical trailer for the movie.