If the Czech version says: Je to OK být vážné a svaté během významných bitů, ale jakmile formality v průběhu, je to stejně OK slavit! Shine na!; then the English version should say: Having a little giggle even, in between the tears of joy. It's OK to be solemn and sacred during the important bits, but once the formalities are over, it's equally OK to celebrate! Shine on!