wiping off phone or computer will probably raise red flags more than anything else...
dozens of years ago, back in my high school days, I was a horny teenager. I barely get passing grades because I didn't care. What I did care about was getting laid. A lot. (something which I would live to regret later for different reasons)
Anyway, I would "entertain" a girl and immediately clean up my bed, to avoid my parents' suspicions. Eventually, my parents caught on and realized that whenever my bed was clean, I must had a girl there that afternoon.