Mr.MyKeal is right,your thumb is soft tissue,I've never lit one off with my thumb.I can see how a dowel could be used by someone w/a dexterity issue but I have to believe the dowel would be more likely to detonate the cap than one's thumb since it's not soft.I just use the proper size nipples or caps ,give em a pinch and some thumb pressure.They have always gone bang when I wanted them to.Best regards,JA