You can ask Bobbie to come to you in the Phone tab (right upper side) then you'll need to "smoke with her" And if u got smth in your fridge or inventory she'll ask you to feed her. Also u can work not for likeability but for tummy size:
1) give her few alcohol drinks (it gives an ability to inflate much more. Don't really remember but smth like up to 150% from standard max size) Also u can buy pack for 80$ (don't want to call these plants🌱, hehe) And give it to her (Being high is also good got belly size)
2) put in her as much food and drinks as you can buy (and don't forget to put a lot of gas pills into dishes)