Thrombosed veins from pumping?

Hello all,

I have begun pumping and although I have not gotten any thrombosed veins, some of my veins feel very sore and stringy after a pump session. I am using a standard 3-6 Hg of vacuum, being careful to not overdo it.

I am at the upper limit for girth for my tube size (I’m around 5.4” and using a 1.75” tube), however my tube flares down to a 1.5” base. While some of the veins feeling stressed are near the glans, I also have a few more down by the base of the cylinder which get sore. Come to think of it, the base where the cylinder sits stays a bit sore for a while after pumping. It’s not cutting into my fat pad, rather, it’s like it’s cutting into my shaft (I don’t know which is worse!).

Does it sound like an issue with form, or poor choice in cylinder? I’m using a JD cylinder from Picturebrite, it was a good price but I’m not sure I can handle the flared end. Thank you in advance for any help.