Hello,
The player must sleep, then tame the bunny (via recipe procedure), then start and cancel the h act with the tamed bunny (after interacting with the bunny to start the hact > hold 0 zero key, located above keys O and P on the keyoboard).
Please check the last of walkthru videos above ( https://www.xvideos.com/video.uableab556c/slavebar_eroge_walkthru_part_2 ) at 12:10 for a gameplay walktrhu.