No, I wouldn’t expect it to be. Suctioning is pretty safe, you can feel when it’s not doing you good, unlike bondage which restricts blood flow and so goes numb. Don’t overpressure it, build up time and repetitions once you know what you can handle. Ten minute stints should be absolutely fine – it’s a nice idea!
You may find it causes some bruising, so just go easy and find out how you get on. Try it and build up from there.
Oh and since I’m making dares today, you can ruin after you’ve managed ten repetitions in a day, and cum once you manage 20 – yes, that’s over three hours suctioning – I hope you like it!