How to say c'mon guys, this is a party so let your hair down and relax a little. in Japanese
1)
さあno dictionary result, likely a conjigated verbno dictionary result, likely a conjigated verb、、(、) Japanese comma君達君達(kimitachi) (pn,adj-no) you/all of you/you all、、(、) Japanese commaパーティーパーティー(patei) (n) partyなな(na) (prt) connects adj to noun/indicates emotion or emphasis/command/prohibitionんだからno dictionary result, likely a conjigated verbno dictionary result, likely a conjigated verb気楽気楽(kiraku) (adj-na,n) carefree/comfortable/at ease/easygoing/happy-go-luckyにに(ni) (prt) indicates such things as location of person or thing, location of short-term action, etc.もっとくつろいでくれよno dictionary result, likely a conjigated verbno dictionary result, likely a conjigated verb。。(。) Japanese period "."
