To pussy out on something or reject ideas due to being afraid of the (possibly harmful) results.
Common excuses to 'Rhysing it' include 'CBF', foot pains, bathroom, "it's too cold outside", "My tracksuit pants are too baggy and might fall off", "I'm pretty sure we've already done that", "You're always pressuring me into things",
Related words: 'To rhys it', 'I rhysed it', 'I am rhysing it', 'I am going to rhys it'
Dave: "Let's go on the tobogan! Apparently it goes pretty fast"
Lenny: "I dunno, I cut my foot and it might start to bleed if we go too fast.."
Dave: "Stop rhysing it! It will be fun!"