From completely covering the glans 'at rest' my foreskin automatically retracts over and behind the corona ridge as I become aroused/erect.
Despite how many 100/1,000 times I've seen it happen I still find it fascination to watch, as from their comments have all my partners who've seen, or caused it to, happen.
There is an exciting sensation as it slips up and over the ridge to join the shaft behind.
The exposed 'inside-out' foreskin is very sensitive
Although the skin of the shaft is fully stretched by the erection the added foreskin can be pulled, either manually or by fucking, back over the ridge, or be pulled further back.
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