New Delhi: In June, 2015 during an ODI match between Bangladesh and India, Virat Kohli took the responsibilities of keeping wickets for the first time ever, since MS Dhoni had to depart for an over for a reported toilet break.
The incident took place at the Sher-e-Bangla Stadium, when Kohli donned the unfamiliar wicket-keeping gloves and stood behind the stumps as pacer Umesh Yadav was bowling the 44th over. Kohli stood far behind the stumps and unlike full-time wicket keepers, didn't put on pads.
Here's the video of the incident:-
The ICC or BCCI dont' really have any defined laws for toilet breaks in between a cricket match.