If someone is as cool as a cucumber, they don't get worried by anything.
b) Have your cake and eat too
If someone wants to have their cake and eat it too, they want everything their way, especially when their wishes are contradictory
c) In a Pickle
If you are in a pickle, you are in some trouble or a mess.
d) Take a cake
Be the most outstanding in some respect, either the best or the worst.That advertising slogan really took the cake.
What a mess they made of the concert—that takes the cake!
This expression alludes to a contest called a cakewalk, in which a cake is the prize. Its figurative use, for something either excellent or outrageously bad, dates from the 1880s.
e) Sell like hot cakes
If something is selling like hotcakes, it is very popular and selling very well.
f) As flat as a Pancake
It is so flat that it is like a pancake- there is no head on that beer it is as flat as a pancake.
g) Take something with a grain of salt / pinch of salt
If you should take something with a grain of salt, you shouldn't necessarily believe it all.
h) Like two peas in a pod
Things that are like two peas in a pod are very similar or identical.