Green’s Dictionary of Slang

stimulate v.

(US) to drink alcohol.

1839		Marryat Diary Amer. Series 1 II 224: [Examples of American language.] ‘He stimulates too much.’ ‘He dissipates awfully.’ And they are very fond of using the noun as a verb, as— ‘I suspicion that's a fact’ .
1891		Morn. Post (London) 18 Feb. 2/3: American invitations to drink [...] ‘Let us stimulate’.
1916		Broadford Courier (Brisbane) 14 Apr. 1/4: There are many ways you can ask a friend to have a drink [...] ‘Let us stimulate’.

In derivatives

stimulated (adj.)

(US) a euph. for drunk.

a.1856

Burlington Sentinel in Hall (1856) 461: We give a list of a few of the various words and phrases which have been in use, at one time or another, to signify some stage of inebriation: [...] stimulated.