Ken had started his handiwork right away after Lensa's pants were pulled down. He tried inserting one of his fingers into her butthole as soon as he found it.
Lensa wasn't expecting her rear entrance to be breached like this at that time. As a result, the hole puckered up and made it difficult for Ken's finger to gain an entry.
"Relax dear. It's just us."
Ken tried to comfort her while he traced the edges of her butthole with his fingers. Her pussy had gotten moist by then and some of the pussy juices had made it till the rear entrance. Ken was using that liquid as a lubricant to soothe his entrance in advance.
"What… why are you trying to put your finger in there? There's a better place nearby, you know."
Lensa wanted Ken to excite her pussy instead of what he was doing right now. But Ken's finger was adamant in entering the first cave it had touched upon from behind.