Practise? There was a barely concealed implication that they would keep doing this. That it would become something more long term- even just sexually, if nothing more- and that thought was an exciting one. To have gone from thinking he would never seem him again, to having him pressed up against him in the shower, promising to give him head, more than once- "OhGod-" he gasped. And then the thought of them at the base, the risks, the idea of him sucking him off somewhere they could be caught- it was making him harder by the second.
Swoff hadn't really caught on to the time travel aspect of the island. Yes, Eames looked older, but war did that to people, especially when he knew that Eames had been injured.
And then Eames was going down, and Swoff's heart-rate picked up instantly. The shower was slippery and tiled and there was nothing he could really grip on to, so one hand went to Eames' shoulder, holding onto him tightly, the other hand balancing him against the wall. He gasped with every movement of Eames' mouth across his stomach, his thighs- and then a wet warmth enveloped him and he was sure he saw stars. "Fuck!" Eames' moan sent shivers right through him. The pleasure was intense, and the hot water streaming down his body seemed to be emphasising every shiver and tingle.