The placement is just below the Glans to the bottom left, the skin moves over it, it is about 1.5 cm long x 2mm thick, it eventually breaks off from the shaft slides around under the skin and gets lost but another appears in it's place a bit later. I have been tested for STD's and have not had unprotected sex so I doubt it's an STD.

I saw a doctor some years ago about it and he said it was a sclerosing lymph node and I have searched it and found a similar thing is could a Lymphocele, but can these break loose and float away only to have another reappear in the same spot?

I'd add that there is no pain from the lump.

I've read that when pressure is applied the lymphocele appears to go away - not necessarily "break loose and float away" since a lymph gland can't really do that. And that they seem to be more prominent during sex/right after sex or during masturbation/right after masturbation - which would make sense since during those activities there's more blood flow to the area.

Thank you, I think you are right, I just tested out that theory by getting an erection then applying pressure and it did move it.
I think a lymphocele seems probable now and this is a good solution even if only temporary?