In Galatians 5:16f, we are told that if we are living in the Spirit we will not gratify the desires of the sinful nature. We are also told that the two—the Spirit and the sinful nature—contend against each other with different desires. Paul goes on to say, in 5:24, those who belong to Christ Jesus have crucified the sinful nature, with its passions and desires.
The last part gives a graphic image I’ll try to share. Crucifixion was a familiar punishment in Paul’s day. Every major city would have crosses of dead and dying flanking the gates to warn those entering the city what could happen. Those reading Paul’s letter would know this and see crucifixion as certain death—no one came off a cross alive. They would also be aware that once dead, most were left on the cross to rot. Paul tells them, in light of this, that their sinful nature had been placed on the cross and remained there. Our sinful natures are dead and hanging on the cross to rot. When we choose to surrender to sinful desires we choose to remove them from the cross and play with them. The pleasure we get is in spite of the fact that we are playing with a corpse.