Recently, during an autumn holiday, I went on a hot springs trip with my wife—the first since we got married. While we were relaxing, my wife briefly looked away, and in that instant, I ended up taking my "first chonmage" (headbutt to the groin). To my own shock and intense embarrassment, my crotch became strongly erect. Perhaps this was the moment my inner NTR (cuckold) fetish awakened.