This adds another new layer of fun to using an onahole, it usually lets me hold back for 40 minutes more than usual, however I would suggest you don't keep it for too long or you could hurt yourself (more than 3-4 hours). Good material it lasted me more than 6 months.
It's alright, nothing really all to great about it. I don't know if i'm a powerful cummer or not but I felt as if this was only able to hold me back for about 10-15 min. longer then usual. Honestly I feel that if you really want to hold yourself back that you are better off just using a rubber band. But I mean it could be just me.. Give it a try and decide for yourselves.