Lianelle has firm breasts on her overall toned and athletic body. Investigating them will also cause her to start wrapping her legs around Mays legs and making sounds into the kisses.
Lianelle's thoughts, meanwhile... Lianelle thinks May is extremely hot and also, importantly to Lianelle right now, good. She would have been interested in sex with May before that became clear - she wants to have sex with lots of people and also champions and monsters and this is almost never a good idea. Outside of the precious days she spends with a real body she can't have sex at all, can't even feel horny, and she hates that so much. Lianelle learned from personal experience that people mind if you just ask them to have sex casually when you first meet, and sometimes they will say yes even though they don't actually want to, so she doesn't do that anymore.
In this moment she is very much enjoying May exploring her boobs which should be explored that's great and feels great, and also she is hoping May enjoys her body in general since she's quite proud of it. She's also jealous of whatever May is feeling from the guiding and is planning on asking her to try projecting the feeling at Lianelle sometime.
And lastly, as she sends all this, she feels... free, to just be able to share her thoughts in this form. It's one of the best parts of the bond.