calm
keep one's pants on
keep one's hair on
encalm
salve
quieten
tranquilize
calm down
quiet
still
tranquillize
lull
tranquillise
placify
calmen
keep one's knickers on
keep one's shirt on
take a breath
relax
chillax
slow one's roll
unruffle
sile
smooth
lay chilly
get ahold of oneself
keep one's head
hold one's nerve
settle
peacen
subside
have one's wits about one
bestill
compose
sort oneself out
allay
keep a cool head
let go
calm your farm
untranquilize
defreak
soothe
pour oil on troubled waters
recompose
simmer down
cool it
settle down
cool off
chill out
gentle