Looking for two doujins. First is about teacher taking class on field trip. While class is away he is banging tour guide in the bus, but girl who have crush on him is hidden in bus. Second is just short story of boy and girl having sex in bear costume.
This would be the first one you described
"Shuugakuryokou"
sorry but cant help with the 2nd one
You can find this at hbrowse by searching "Shuugakuryokou"
>>14067060
>>14067078
It's not the one i'm looking for but thanks anyway.