Her giant bare feet

Being so tall, Laura's shoe size is big enough to be way out of the norm on their own. At Erik's current size, it is like being between two monuments of odorous wrinkled material. Each of the gigantic toes dwarfs him in size, and he starts to snap out of it, he's been in awe of the sleeping giantess's exposed feet for way too long. One too many nights of shamelessly peeking out of the hallway to see Laura's size 12 feet flexing on the living room table, dripping with sweat from her workout. She probably would've appreciated Erik offering a massage but it would've been too awkward and too bold to do something like that...

Now he is between the objects of his secret admiration, they're just over 40-ft tall and capable of flattening him in an instant if their unaware owner happened to do so in her sleep. It should be warning enough to leap off the bed, land somewhere soft hopefully, and start this adventure from scratch. But hormones for this bizarre once-in-a-lifetime chance take ahold of him. Erik runs from the edge of the bed with as much speed until he is in the shadow of the nearest titanic foot. It is like being in the presence of a whale or a long slab of marble in a cavern. His heart is beating fast as he runs a hand down the only part he can really reach, the tough, dry bottom of Laura's heel. He starts with a poke, so unnoticeable thanks to the thick layer of skin and his size. Feeling braver, he begins to use both hands until he is effectively karate-chopping and digging his fingers onto the heel. Sometimes he looks up and is unaware of his size again... Erik is so small that it would probably take him several hours to climb onto the wrinkles and make it to the top of Laura's toes. Intoxicated with the foot sweat and hormones, he rubs the toughest parts of the giantess's heels while she sleeps away without a care in the world. Or knowledge of her son's secret night-time activity...

Erik is so into working on his gigantic mom's heels that he doesn't notice that up along the bed,_ the bedsheets are rising _in the area of Laura's pelvis and hips. It could be suspected for a knee if her legs weren't already in position.