Is it okay to poke holes in clouds while flying with my students?   

No, it's not 'okay', especially with students on an instructional flight.

Minimum visibility:

91:155 For helicopters: Day 1⁄2 statute mile Clear of clouds

You're violating the FARs and endangering lives- you don't know what else, who else is in that cloud. That's what you're obligated to the student to teach and you should learn as quickly as possible.

If you want to practice instrument skills, there are ways to do it safely.

If this isn't somebody's idea of a joke, a troll, it's an advertisement of future Darwin Award.