A dictionary of Confusable Phrases: More Than 10,000 Idioms and Collocations

help oneself • one can’t help oneself
help oneself —serve oneself with food, drink, etc.: Once he
had (quite generously) helped himself, the others at the table
began to join in, keeping him from only consuming half the
bottle on his own accord.
one can’t help oneself —one can’t refrain from doing smth.:
The man turned himself in possibly because he knew what he
was doing was wrong, but couldn’t help himself.
help someone off something • help someone off
with something
help someone off something —help a person to leave smth.:
Two males helped him off the boat, then led the man ashore,
through the waist deep water.
help someone off with something —assist a person in taking
off clothing: He shut the front door and turned to help her
off with her coat.
help someone to something • help someone with
something
help someone to something —serve a person with food, drink,
etc.: “Shall I give you some strawberries, Mr. Hervey,” said
Lady Anne, “or will you let Helena help you to some cher-
ries?”
Note: 
The expression does not fully correlate in meaning with
the phrase help oneself to something—
1
. give oneself smth. such
as food (without permission): The aroma was irresistible and I
quickly helped myself to some crab meat on the table. 2. steal
smth.: The robbers helped themselves to an undisclosed
amount of cash, believed to be several thousand dollars, before
fleeing the area.
help someone with something —
1
. make it easier for a person
to do smth. by providing assistance: Butch sent Willie some
books to help him with grammar. 2. help a person to put on
or take off clothing: Someone helped Janson with his coat,
and he left the hall.