Hi, I have been doing these stretches for a week now and yesterday, when I masturbated and eventually ejaculated, I noticed a tense feeling on uthe underside of my penis, perhaps around the frenulum. I assumed this was due to a short frenulum so I began stretching it as well. But, this morning when I tried to get on with stretching, i realised that my frenulum was kind of big and red. And it's a bit sensitive to pull the skin out. Should I take a break or something?

That must have been a marathon session to have caused the frenulum to swell up and become irritated. What did you do that was different? Was it the stretching of the frenulum?

Perhaps you are applying too much tension. This process requires only gentle tugging, so if it's beyond that, back off. I think laying off for a day or two might be in your best interest. When the little guy is back to normal, resume with less intensity.