Yeah I used to say 'um' in front of words to avoid a block. Will that stopped working as well I added 'the' which resulted in 'the um'. My "friends" made it into a rap. In hindsight, I strongly discourage trying to cheat around your stutter. For me it only exacerbated the problem over time. If you're having trouble with just those specific sounds, try going the other way. Instead of hitting them aggressively, hit them softly. Don't bring your lips all the way together for B. For G and D, keep your teeth and tongue from locking or closing. Keep your air flowing. Mushmouth the sounds a little bit.