Traditionally done by men who look like small cars and smell like gym socks, weightlifting has a bad sexiness ranking. A shame, really, given its enormous potential. The thing is, if you plan to do it at home, make sure it's the kind of lifting suited home rather than gym.
First, roll out a yoga mat so that the lifter can kneel on it comfortably. If you have 1970s thick carpeting you can skip this step, but you might want to have your lungs checked out.
Once he's on his knees, tie his hands behind his back and blindfold him.
Next, bring out a sack of marbles.
Tie a soft strap of silk, rubber, or whatever you can find, around the base of the cock and under the scrotum, securely fastened but not too tight. If there are piercings see how you might use them for attaching things to as well. Leave a good length of the strap hanging down well below the weightlifter's balls.
Empty the sack of marbles, and attach it to the end of this strap, making sure there's an opening at the top of the bag.
When the weightlifter is in position, leaning forward, blindfolded and restrained, start adding marbles to the bag, one by one. The weight will gradually accumulate, pulling down on his cock and balls.
Don't rush. This is a tease, and it will leave him helplessly engorged.
Stick in a butt plug for garnish, well-lubricated.
If he's been a particularly good boy suck his cock until he comes, helplessly.