3 sentences

1. 朋友们久别重逢，在席间开怀畅饮。

   péng​yǒu​men jiǔ​bié​chóng​féng, zài xí​jiān kāi​huái chàng​yǐn.

   Friends reunited after a long separation and drank heartily during the meal.

   Source: Dong Chinese Dictionary

2. 古人常以浮大白来形容开怀畅饮。

   gǔ​rén cháng yǐ fú dà​bái lái xíng​róng kāi​huái chàng​yǐn.

   Ancients often used the phrase 'draining a large cup' to describe drinking to one's heart's content.

   Source: Dong Chinese Dictionary

3. 听了他的笑话，大家都开怀大笑起来。

   tīng le tā de xiào​hua, dà​jiā dōu kāi​huái dà​xiào qi​lai.

   Everyone burst into hearty laughter after hearing his joke.

   Source: Dong Chinese Dictionary