But you
do seem to be describing a degree of short frænulum (sometimes "medicalised" to make it sound like some disease by calling it "frænulum breve") which is causing you a problem. I can see that there are degrees of the problem such as yours which can cause trouble
even if you take due care to use adequate lubrication, though the lack of same is mostly the basis of discomfort.
And this condition
mostly goes with a foreskin which has not been retracted through childhood and puberty, particularly when the foreskin itself is tight and the fellow has not realised that it
should be pulled back. If the foreskin retracts with an erection, then the frequent erections that occur during sleep would usually be sufficient to cause the frænulum to lengthen to a comfortable degree. So I suspect you have a story of not retracting (much) until late in life?

As in previous threads,
this is the "exercise" we feel to be most efficient for stretching the frænulum.
My first thought regarding your concern about the possibility of tearing the frænulum is that it is not as catastrophic as is often made out, particularly when the corresponding occurrence in women is actually lauded by tradition! I have discussed this - and the pros and cons of surgical release - many times before as this
Google search reveals, and
this thread is quite a typically rollicking discussion!
It explains my point that in general, skin - including that comprising the frænulum - behaves in a manner which befits need and that if either torn, cut or stretched it will simply heal in due course and continue to function. In general, a healed scar is in the
middle term, somewhat stronger than the original state, but it takes a while before to achieve this (so there is no advantage to surgery - it puts you "out of action" for the same time as for a tear) and in the long term eventually "remodels" to match the surrounds (so there is no benefit either in surgery to "make it stronger").
Stretching in the manner we recommend (short of causing significant pain or visible tearing) involves not the repair process of scarring, but the normal process of growth in response to tension, so will neither weaken nor cause loss of function as the process occurs - in other words, you can still
use the body part during the stretching program. This is surely a
major advantage over surgery!